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Peterson, Peter authoredPeterson, Peter authored
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MaxEnt.cpp 27.15 KiB
#include "MantidAlgorithms/MaxEnt.h"
#include "MantidAPI/EqualBinSizesValidator.h"
#include "MantidAPI/MatrixWorkspace.h"
#include "MantidAPI/TextAxis.h"
#include "MantidAPI/WorkspaceFactory.h"
#include "MantidAlgorithms/MaxEnt/MaxentEntropyNegativeValues.h"
#include "MantidAlgorithms/MaxEnt/MaxentEntropyPositiveValues.h"
#include "MantidAlgorithms/MaxEnt/MaxentSpaceComplex.h"
#include "MantidAlgorithms/MaxEnt/MaxentSpaceReal.h"
#include "MantidAlgorithms/MaxEnt/MaxentTransformFourier.h"
#include "MantidHistogramData/LinearGenerator.h"
#include "MantidKernel/BoundedValidator.h"
#include "MantidKernel/ListValidator.h"
#include "MantidKernel/UnitFactory.h"
#include "MantidKernel/VectorHelper.h"
#include <gsl/gsl_linalg.h>
#include <numeric>
namespace Mantid {
namespace Algorithms {
using Mantid::HistogramData::LinearGenerator;
using Mantid::HistogramData::Points;
using namespace API;
using namespace Kernel;
// Register the algorithm into the AlgorithmFactory
DECLARE_ALGORITHM(MaxEnt)
namespace {
// Maps defining the inverse caption and label for the reconstructed image
// Example:
// The input workspaces (X axis) is in (Time, s)
// The output image should be in (Frequency, Hz)
// Defines the new caption
std::map<std::string, std::string> inverseCaption = {{"Time", "Frequency"},
{"Frequency", "Time"},
{"d-Spacing", "q"},
{"q", "d-Spacing"}};
// Defines the new label
std::map<std::string, std::string> inverseLabel = {{"s", "Hz"},
{"microsecond", "MHz"},
{"Hz", "s"},
{"MHz", "microsecond"},
{"Angstrom", "Angstrom^-1"},
{"Angstrom^-1", "Angstrom"}};
}
//----------------------------------------------------------------------------------------------
/// Algorithm's name for identification. @see Algorithm::name
const std::string MaxEnt::name() const { return "MaxEnt"; }
/// Algorithm's version for identification. @see Algorithm::version
int MaxEnt::version() const { return 1; }
/// Algorithm's category for identification. @see Algorithm::category
const std::string MaxEnt::category() const { return "Arithmetic\\FFT"; }
/// Algorithm's summary for use in the GUI and help. @see Algorithm::summary
const std::string MaxEnt::summary() const {
return "Runs Maximum Entropy method on every spectrum of an input workspace. "
"It currently works for the case where data and image are related by a"
" 1D Fourier transform.";
}
//----------------------------------------------------------------------------------------------/** Initialize the algorithm's properties.
*/
void MaxEnt::init() {
// X values in input workspace must be (almost) equally spaced
const double warningLevel = 0.01;
const double errorLevel = 0.5;
declareProperty(
make_unique<WorkspaceProperty<>>(
"InputWorkspace", "", Direction::Input,
boost::make_shared<EqualBinSizesValidator>(errorLevel, warningLevel)),
"An input workspace.");
declareProperty("ComplexData", false,
"If true, the input data is assumed to be complex and the "
"input workspace is expected to have an even number of "
"histograms (2N). Spectrum numbers S and S+N are assumed to "
"be the real and imaginary part of the complex signal "
"respectively.");
declareProperty("ComplexImage", true,
"If true, the algorithm will use complex images for the "
"calculations. This is the recommended option when there is "
"no prior knowledge about the image. If the image is known "
"to be real, this option can be set to false and the "
"algorithm will only consider the real part for "
"calculations.");
declareProperty("PositiveImage", false,
"If true, the reconstructed image is only allowed to take "
"positive values. It can take negative values otherwise. "
"This option defines the entropy formula that will be used "
"for the calculations (see next section for more details).");
declareProperty("AutoShift", false,
"Automatically calculate and apply phase shift. Zero on the "
"X axis is assumed to be in the first bin. If it is not, "
"setting this property will automatically correct for this.");
auto mustBePositive = boost::make_shared<BoundedValidator<size_t>>();
mustBePositive->setLower(0);
declareProperty(make_unique<PropertyWithValue<size_t>>(
"ResolutionFactor", 1, mustBePositive, Direction::Input),
"An integer number indicating the factor by which the number "
"of points will be increased in the image and reconstructed "
"data");
auto mustBeNonNegative = boost::make_shared<BoundedValidator<double>>();
mustBeNonNegative->setLower(1E-12);
declareProperty(make_unique<PropertyWithValue<double>>(
"A", 0.4, mustBeNonNegative, Direction::Input),
"A maximum entropy constant");
declareProperty(make_unique<PropertyWithValue<double>>(
"ChiTarget", 100.0, mustBeNonNegative, Direction::Input),
"Target value of Chi-square");
declareProperty(make_unique<PropertyWithValue<double>>(
"ChiEps", 0.001, mustBeNonNegative, Direction::Input),
"Required precision for Chi-square");
declareProperty(
make_unique<PropertyWithValue<double>>(
"DistancePenalty", 0.1, mustBeNonNegative, Direction::Input),
"Distance penalty applied to the current image at each iteration.");
declareProperty(make_unique<PropertyWithValue<double>>(
"MaxAngle", 0.05, mustBeNonNegative, Direction::Input),
"Maximum degree of non-parallelism between S and C.");
mustBePositive = boost::make_shared<BoundedValidator<size_t>>();
mustBePositive->setLower(1);
declareProperty(make_unique<PropertyWithValue<size_t>>(
"MaxIterations", 20000, mustBePositive, Direction::Input),
"Maximum number of iterations.");
declareProperty(make_unique<PropertyWithValue<size_t>>("AlphaChopIterations",
500, mustBePositive,
Direction::Input),
"Maximum number of iterations in alpha chop.");
declareProperty(
make_unique<WorkspaceProperty<>>("EvolChi", "", Direction::Output),
"Output workspace containing the evolution of Chi-sq.");
declareProperty(
make_unique<WorkspaceProperty<>>("EvolAngle", "", Direction::Output),
"Output workspace containing the evolution of "
"non-paralellism between S and C.");
declareProperty(make_unique<WorkspaceProperty<>>("ReconstructedImage", "",
Direction::Output),
"The output workspace containing the reconstructed image.");
declareProperty(make_unique<WorkspaceProperty<>>("ReconstructedData", "",
Direction::Output),
"The output workspace containing the reconstructed data.");
}
//----------------------------------------------------------------------------------------------
/** Validate the input properties.
*/
std::map<std::string, std::string> MaxEnt::validateInputs() {
std::map<std::string, std::string> result;
MatrixWorkspace_sptr inWS = getProperty("InputWorkspace");
if (inWS) {
// If the input signal is complex, we expect an even number of histograms
// in the input workspace
size_t nhistograms = inWS->getNumberHistograms();
bool complex = getProperty("ComplexData");
if (complex && (nhistograms % 2))
result["InputWorkspace"] = "The number of histograms in the input "
"workspace must be even for complex data";
}
return result;
}
//----------------------------------------------------------------------------------------------
/** Execute the algorithm.
*/
void MaxEnt::exec() {
// MaxEnt parameters
// Complex data?
const bool complexData = getProperty("ComplexData");
// Complex image?
const bool complexImage = getProperty("ComplexImage");
// Image must be positive?
const bool positiveImage = getProperty("PositiveImage");
// Autoshift
const bool autoShift = getProperty("AutoShift");
// Increase the number of points in the image by this factor
const size_t resolutionFactor = getProperty("ResolutionFactor");
// Background (default level, sky background, etc)
const double background = getProperty("A");
// Chi target
const double chiTarget = getProperty("ChiTarget");
// Required precision for Chi arget const double chiEps = getProperty("ChiEps");
// Maximum degree of non-parallelism between S and C
const double angle = getProperty("MaxAngle");
// Distance penalty for current image
const double distEps = getProperty("DistancePenalty");
// Maximum number of iterations
const size_t niter = getProperty("MaxIterations");
// Maximum number of iterations in alpha chop
const size_t alphaIter = getProperty("AlphaChopIterations");
// Number of spectra and datapoints
// Read input workspace
MatrixWorkspace_const_sptr inWS = getProperty("InputWorkspace");
// Number of spectra
size_t nspec = inWS->getNumberHistograms();
// Number of data points - assumed to be constant between spectra or
// this will throw an exception
size_t npoints = inWS->blocksize() * resolutionFactor;
// Number of X bins
const size_t npointsX = inWS->isHistogramData() ? npoints + 1 : npoints;
// Is our data space real or complex?
MaxentSpace_sptr dataSpace;
if (complexData) {
dataSpace = std::make_shared<MaxentSpaceComplex>();
} else {
dataSpace = std::make_shared<MaxentSpaceReal>();
}
// Is our image space real or complex?
MaxentSpace_sptr imageSpace;
if (complexImage) {
imageSpace = std::make_shared<MaxentSpaceComplex>();
} else {
imageSpace = std::make_shared<MaxentSpaceReal>();
}
// The type of transform. Currently a 1D Fourier Transform
MaxentTransform_sptr transform =
std::make_shared<MaxentTransformFourier>(dataSpace, imageSpace);
// The type of entropy we are going to use (depends on the type of image,
// positive only, or positive and/or negative)
MaxentEntropy_sptr entropy;
if (positiveImage) {
entropy = std::make_shared<MaxentEntropyPositiveValues>();
} else {
entropy = std::make_shared<MaxentEntropyNegativeValues>();
}
// Entropy and transform is all we need to set up a calculator
MaxentCalculator maxentCalculator = MaxentCalculator(entropy, transform);
// Output workspaces
MatrixWorkspace_sptr outImageWS;
MatrixWorkspace_sptr outDataWS;
MatrixWorkspace_sptr outEvolChi;
MatrixWorkspace_sptr outEvolTest;
nspec = complexData ? nspec / 2 : nspec;
outImageWS =
WorkspaceFactory::Instance().create(inWS, 2 * nspec, npoints, npoints);
outDataWS =
WorkspaceFactory::Instance().create(inWS, 2 * nspec, npointsX, npoints);
outEvolChi = WorkspaceFactory::Instance().create(inWS, nspec, niter, niter);
outEvolTest = WorkspaceFactory::Instance().create(inWS, nspec, niter, niter);
npoints = complexImage ? npoints * 2 : npoints;
outEvolChi->setPoints(0, Points(niter, LinearGenerator(0.0, 1.0)));
for (size_t s = 0; s < nspec; s++) {
// Start distribution (flat background) std::vector<double> image(npoints, background);
std::vector<double> data;
std::vector<double> errors;
if (complexData) {
data = toComplex(inWS, s, false); // false -> data
errors = toComplex(inWS, s, true); // true -> errors
} else {
data = inWS->y(s).rawData();
errors = inWS->e(s).rawData();
}
// To record the algorithm's progress
std::vector<double> evolChi(niter, 0.);
std::vector<double> evolTest(niter, 0.);
// Progress
Progress progress(this, 0.0, 1.0, niter);
// Run maxent algorithm
for (size_t it = 0; it < niter; it++) {
// Iterates one step towards the solution. This means calculating
// quadratic coefficients, search directions, angle and chi-sq
maxentCalculator.iterate(data, errors, image, background);
// Calculate delta to construct new image (SB eq. 25)
double currChisq = maxentCalculator.getChisq();
auto coeffs = maxentCalculator.getQuadraticCoefficients();
auto delta = move(coeffs, chiTarget / currChisq, chiEps, alphaIter);
// Apply distance penalty (SB eq. 33)
delta = applyDistancePenalty(delta, coeffs, image, background, distEps);
// Update image
auto dirs = maxentCalculator.getSearchDirections();
image = updateImage(image, delta, dirs);
// Record the evolution of Chi-square and angle(S,C)
double currAngle = maxentCalculator.getAngle();
evolChi[it] = currChisq;
evolTest[it] = currAngle;
// Stop condition, solution found
if ((std::abs(currChisq / chiTarget - 1.) < chiEps) &&
(currAngle < angle)) {
break;
}
// Check for canceling the algorithm
if (!(it % 1000)) {
interruption_point();
}
progress.report();
} // iterations
// Get calculated data
auto solData = maxentCalculator.getReconstructedData();
auto solImage = maxentCalculator.getImage();
// Populate the output workspaces
populateDataWS(inWS, s, nspec, solData, complexData, outDataWS);
populateImageWS(inWS, s, nspec, solImage, complexImage, outImageWS,
autoShift);
// Populate workspaces recording the evolution of Chi and Test
// X values
outEvolChi->setSharedX(s, outEvolChi->sharedX(0)); outEvolTest->setSharedX(s, outEvolChi->sharedX(0));
// Y values
outEvolChi->setCounts(s, std::move(evolChi));
outEvolTest->setCounts(s, std::move(evolTest));
// No errors
} // Next spectrum
setProperty("EvolChi", outEvolChi);
setProperty("EvolAngle", outEvolTest);
setProperty("ReconstructedImage", outImageWS);
setProperty("ReconstructedData", outDataWS);
}
//----------------------------------------------------------------------------------------------
/** Returns a given spectrum as a complex number
* @param inWS :: [input] The input workspace containing all the spectra
* @param spec :: [input] The spectrum of interest
* @param errors :: [input] If true, returns the errors, otherwise returns the
* counts
* @return : Spectrum 'spec' as a complex vector
*/
std::vector<double> MaxEnt::toComplex(API::MatrixWorkspace_const_sptr &inWS,
size_t spec, bool errors) {
const size_t numBins = inWS->y(0).size();
std::vector<double> result(numBins * 2);
if (inWS->getNumberHistograms() % 2)
throw std::invalid_argument(
"Cannot convert input workspace to complex data");
size_t nspec = inWS->getNumberHistograms() / 2;
if (!errors) {
for (size_t i = 0; i < numBins; i++) {
result[2 * i] = inWS->y(spec)[i];
result[2 * i + 1] = inWS->y(spec + nspec)[i];
}
} else {
for (size_t i = 0; i < numBins; i++) {
result[2 * i] = inWS->e(spec)[i];
result[2 * i + 1] = inWS->e(spec + nspec)[i];
}
}
return result;
}
/** Bisection method to move delta one step closer towards the solution
* @param coeffs :: [input] The current quadratic coefficients
* @param chiTarget :: [input] The requested Chi target
* @param chiEps :: [input] Precision required for Chi target
* @param alphaIter :: [input] Maximum number of iterations in the bisection
* method (alpha chop)
* @return : The increment length to be added to the current image
*/
std::vector<double> MaxEnt::move(const QuadraticCoefficients &coeffs,
double chiTarget, double chiEps,
size_t alphaIter) {
double aMin = 0.; // Minimum alpha
double aMax = 1.; // Maximum alpha
// Dimension, number of search directions
size_t dim = coeffs.c2.size().first;
std::vector<double> deltaMin(dim, 0); // delta at alpha min
std::vector<double> deltaMax(dim, 0); // delta at alpha max
double chiMin = calculateChi(coeffs, aMin, deltaMin); // Chi at alpha min
double chiMax = calculateChi(coeffs, aMax, deltaMax); // Chi at alpha max
double dchiMin = chiMin - chiTarget; // max - target
double dchiMax = chiMax - chiTarget; // min - target
if (dchiMin * dchiMax > 0) {
// ChiTarget could be outside the range [chiMin, chiMax]
if (fabs(dchiMin) < fabs(dchiMax)) {
return deltaMin;
} else {
return deltaMax;
}
// throw std::runtime_error("Error in alpha chop\n");
}
// Initial values of eps and iter to start while loop
double eps = 2. * chiEps;
size_t iter = 0;
// Bisection method
std::vector<double> delta(dim, 0); // delta at current alpha
while ((fabs(eps) > chiEps) && (iter < alphaIter)) {
double aMid = 0.5 * (aMin + aMax);
double chiMid = calculateChi(coeffs, aMid, delta);
eps = chiMid - chiTarget;
if (dchiMin * eps > 0) {
aMin = aMid;
dchiMin = eps;
}
if (dchiMax * eps > 0) {
aMax = aMid;
dchiMax = eps;
}
iter++;
}
// Check if move was successful
if ((fabs(eps) > chiEps) || (iter > alphaIter)) {
throw std::runtime_error("Error encountered when calculating solution "
"image. No convergence in alpha chop.\n");
}
return delta;
}
/** Calculates Chi given the quadratic coefficients and an alpha value by
* solving the matrix equation A*b = B
* @param coeffs :: [input] The quadratic coefficients
* @param a :: [input] The alpha value
* @param b :: [output] The solution
* @return :: The calculated chi-square
*/
double MaxEnt::calculateChi(const QuadraticCoefficients &coeffs, double a,
std::vector<double> &b) {
size_t dim = coeffs.c2.size().first;
double ax = a;
double bx = 1 - ax;
Kernel::DblMatrix A(dim, dim);
Kernel::DblMatrix B(dim, 1);
// Construct the matrix A and vector B such that Ax=B
for (size_t k = 0; k < dim; k++) {
for (size_t l = 0; l < dim; l++) {
A[k][l] = bx * coeffs.c2[k][l] - ax * coeffs.s2[k][l];
}
B[k][0] = -bx * coeffs.c1[k][0] + ax * coeffs.s1[k][0];
}
// Alternatives I have tried:
// Gauss-Jordan
// LU
// SVD seems to work better
// Solve using SVD
b = solveSVD(A, B);
// Now compute Chi
double ww = 0.;
for (size_t k = 0; k < dim; k++) {
double z = 0.;
for (size_t l = 0; l < dim; l++) {
z += coeffs.c2[k][l] * b[l];
}
ww += b[k] * (coeffs.c1[k][0] + 0.5 * z);
}
// Return chi
return ww + 1.;
}
/** Solves A*x = B using SVD
* @param A :: [input] The matrix A
* @param B :: [input] The vector B
* @return :: The solution x
*/
std::vector<double> MaxEnt::solveSVD(const DblMatrix &A, const DblMatrix &B) {
size_t dim = A.size().first;
gsl_matrix *a = gsl_matrix_alloc(dim, dim);
gsl_matrix *v = gsl_matrix_alloc(dim, dim);
gsl_vector *s = gsl_vector_alloc(dim);
gsl_vector *w = gsl_vector_alloc(dim);
gsl_vector *x = gsl_vector_alloc(dim);
gsl_vector *b = gsl_vector_alloc(dim);
// Need to copy from DblMatrix to gsl matrix
for (size_t k = 0; k < dim; k++)
for (size_t l = 0; l < dim; l++)
gsl_matrix_set(a, k, l, A[k][l]);
for (size_t k = 0; k < dim; k++)
gsl_vector_set(b, k, B[k][0]);
// Singular value decomposition
gsl_linalg_SV_decomp(a, v, s, w);
// A could be singular or ill-conditioned. We can use SVD to obtain a least
// squares
// solution by setting the small (compared to the maximum) singular values to
// zero
// Find largest sing value
double max = gsl_vector_get(s, 0);
for (size_t i = 0; i < dim; i++) {
if (max < gsl_vector_get(s, i))
max = gsl_vector_get(s, i); }
// Apply a threshold to small singular values
const double THRESHOLD = 1E-6;
double threshold = THRESHOLD * max;
for (size_t i = 0; i < dim; i++)
if (gsl_vector_get(s, i) > threshold)
gsl_vector_set(s, i, gsl_vector_get(s, i));
else
gsl_vector_set(s, i, 0);
// Solve A*x = B
gsl_linalg_SV_solve(a, v, s, b, x);
// From gsl_vector to vector
std::vector<double> delta(dim);
for (size_t k = 0; k < dim; k++)
delta[k] = gsl_vector_get(x, k);
gsl_matrix_free(a);
gsl_matrix_free(v);
gsl_vector_free(s);
gsl_vector_free(w);
gsl_vector_free(x);
gsl_vector_free(b);
return delta;
}
/** Applies a distance penalty
* @param delta :: [input] The current increment
* @param coeffs :: [input] The quadratic coefficients
* @param image :: [input] The current image
* @param background :: [input] The background
* @param distEps :: [input] The distance constraint
* @return :: The new increment
*/
std::vector<double> MaxEnt::applyDistancePenalty(
const std::vector<double> &delta, const QuadraticCoefficients &coeffs,
const std::vector<double> &image, double background, double distEps) {
double sum = 0.;
for (double point : image)
sum += fabs(point);
size_t dim = coeffs.s2.size().first;
double dist = 0.;
for (size_t k = 0; k < dim; k++) {
double sum = 0.0;
for (size_t l = 0; l < dim; l++)
sum -= coeffs.s2[k][l] * delta[l];
dist += delta[k] * sum;
}
auto newDelta = delta;
if (dist > distEps * sum / background) {
for (size_t k = 0; k < delta.size(); k++) {
newDelta[k] *= sqrt(sum / dist / background);
}
}
return newDelta;
}
/**
* Updates the image according to an increment delta
* @param image : [input] The current image as a vector (can be real or complex)
* @param delta : [input] The increment delta as a vector (can be real or* complex)
* @param dirs : [input] The search directions
* @return : The new image
*/
std::vector<double>
MaxEnt::updateImage(const std::vector<double> &image,
const std::vector<double> &delta,
const std::vector<std::vector<double>> dirs) {
std::vector<double> newImage = image;
if (image.empty() || dirs.empty() || (delta.size() != dirs.size())) {
throw std::runtime_error("Cannot calculate new image");
}
// Calculate the new image
for (size_t i = 0; i < image.size(); i++) {
for (size_t k = 0; k < delta.size(); k++) {
newImage[i] = newImage[i] + delta[k] * dirs[k][i];
}
}
return newImage;
}
/** Populates the output workspaces
* @param inWS :: [input] The input workspace
* @param spec :: [input] The current spectrum being analyzed
* @param nspec :: [input] The total number of histograms in the input workspace
* @param result :: [input] The image to be written in the output workspace (can
* be real or complex vector)
* @param complex :: [input] True if the result is a complex vector, false
* otherwise
* @param outWS :: [input] The output workspace to populate
* @param autoShift :: [input] Whether or not to correct the phase shift
*/
void MaxEnt::populateImageWS(MatrixWorkspace_const_sptr &inWS, size_t spec,
size_t nspec, const std::vector<double> &result,
bool complex, MatrixWorkspace_sptr &outWS,
bool autoShift) {
if (complex && result.size() % 2)
throw std::invalid_argument("Cannot write results to output workspaces");
int npoints = complex ? static_cast<int>(result.size() / 2)
: static_cast<int>(result.size());
MantidVec X(npoints);
MantidVec YR(npoints);
MantidVec YI(npoints);
MantidVec E(npoints, 0.);
auto dataPoints = inWS->points(spec);
double x0 = dataPoints[0];
double dx = dataPoints[1] - x0;
double delta = 1. / dx / npoints;
const int isOdd = (inWS->y(0).size() % 2) ? 1 : 0;
double shift = x0 * 2. * M_PI;
if (!autoShift)
shift = 0.;
// X values
for (int i = 0; i < npoints; i++) {
X[i] = delta * (-npoints / 2 + i);
}
// Y values
if (complex) {
for (int i = 0; i < npoints; i++) {
int j = (npoints / 2 + i + isOdd) % npoints; double xShift = X[i] * shift;
double c = cos(xShift);
double s = sin(xShift);
YR[i] = result[2 * j] * c - result[2 * j + 1] * s;
YI[i] = result[2 * j] * s + result[2 * j + 1] * c;
YR[i] *= dx;
YI[i] *= dx;
}
} else {
for (int i = 0; i < npoints; i++) {
int j = (npoints / 2 + i + isOdd) % npoints;
double xShift = X[i] * shift;
double c = cos(xShift);
double s = sin(xShift);
YR[i] = result[j] * c;
YI[i] = result[j] * s;
YR[i] *= dx;
YI[i] *= dx;
}
}
// X caption & label
auto inputUnit = inWS->getAxis(0)->unit();
if (inputUnit) {
boost::shared_ptr<Kernel::Units::Label> lblUnit =
boost::dynamic_pointer_cast<Kernel::Units::Label>(
UnitFactory::Instance().create("Label"));
if (lblUnit) {
lblUnit->setLabel(
inverseCaption[inWS->getAxis(0)->unit()->caption()],
inverseLabel[inWS->getAxis(0)->unit()->label().ascii()]);
outWS->getAxis(0)->unit() = lblUnit;
}
}
outWS->mutableX(spec) = std::move(X);
outWS->mutableY(spec) = std::move(YR);
outWS->mutableE(spec) = std::move(E);
outWS->setSharedX(nspec + spec, outWS->sharedX(spec));
outWS->mutableY(nspec + spec) = std::move(YI);
outWS->setSharedE(nspec + spec, outWS->sharedE(spec));
}
/** Populates the output workspaces
* @param inWS :: [input] The input workspace
* @param spec :: [input] The current spectrum being analyzed
* @param nspec :: [input] The total number of histograms in the input workspace
* @param result :: [input] The reconstructed data to be written in the output
* workspace (can be a real or complex vector)
* @param complex :: [input] True if result is a complex vector, false otherwise
* @param outWS :: [input] The output workspace to populate
*/
void MaxEnt::populateDataWS(MatrixWorkspace_const_sptr &inWS, size_t spec,
size_t nspec, const std::vector<double> &result,
bool complex, MatrixWorkspace_sptr &outWS) {
if (complex && result.size() % 2)
throw std::invalid_argument("Cannot write results to output workspaces");
int npoints = complex ? static_cast<int>(result.size() / 2)
: static_cast<int>(result.size());
int npointsX = inWS->isHistogramData() ? npoints + 1 : npoints;
MantidVec X(npointsX);
MantidVec YR(npoints);
MantidVec YI(npoints);
MantidVec E(npoints, 0.);
double x0 = inWS->x(spec)[0];
double dx = inWS->x(spec)[1] - x0;
// X values
for (int i = 0; i < npointsX; i++) {
X[i] = x0 + i * dx;
}
// Y values
if (complex) {
for (int i = 0; i < npoints; i++) {
YR[i] = result[2 * i];
YI[i] = result[2 * i + 1];
}
} else {
for (int i = 0; i < npoints; i++) {
YR[i] = result[i];
YI[i] = 0.;
}
}
outWS->mutableX(spec) = std::move(X);
outWS->mutableY(spec) = std::move(YR);
outWS->mutableE(spec) = std::move(E);
outWS->setSharedX(nspec + spec, outWS->sharedX(spec));
outWS->mutableY(nspec + spec) = std::move(YI);
outWS->setSharedE(nspec + spec, outWS->sharedE(spec));
}
} // namespace Algorithms
} // namespace Mantid