NetlistWriter: improve readme slightly

    auto to_save = config_.getArray<std::string>("waveform_to_save");

    waveform_to_save_.insert(to_save.begin(), to_save.end());

    // Boolean to execute or not the external uelec simulation

    // Options to add the the uelec simulation command

    if(config_.has("simulator_command")) {

        run_netlist_simulation_ = true;

            // Get pixel address

            auto detector_model = detector_->getModel();

            std::string idx = std::to_string(pixel_index.x() * static_cast<int>(detector_model->getNPixels().Y()) + pixel_index.y());

            std::string idx =

                std::to_string(pixel_index.x() * static_cast<int>(detector_model->getNPixels().Y()) + pixel_index.y());

            if(target_ == Target::SPECTRE) {

                file << source_name_ << "\\<" << idx << "\\> (";

## Description

Integrates micro-electronics simulation elements in the Allpix Squared simulation flow. Allows the user to generate netlists (input file used by an electrical simulator to simulate the behavior of the circuit) from a given netlist template. `SPECTRE` (Cadence environment) and `SPICE` syntaxes are allowed and can be selected using the `target` parameter. This module is mostly intended for analog front-end electrical simulation using the `PixelCharge` object data.

Integrates micro-electronics simulation elements in the Allpix Squared simulation flow. Allows the user to generate netlists (input file used by an electrical simulator to simulate the behavior of the circuit) from a given netlist template. `SPECTRE` (Cadence environment) and `SPICE` syntax are allowed and can be selected using the `target` parameter. This module is mostly intended for analog front-end electrical simulation using the `PixelCharge` object data.

The netlist template needs to be formatted as described and illustrated (`SPECTRE` syntax) below:

--- netlist footer and simulator options ---

```

One way to get a netlist already formatted could be to extract it from the Cadence Virtuoso environment ('schematic' view).

One way to get a netlist already formatted could be to extract it from the Cadence Virtuoso environment ("schematic" view).

A new netlist is written for each event, reusing the header, footer, and circuit description from the netlist template specified with the `netlist_template` parameter. For each fired pixel, a source / circuit instance pair is added to the template.

The generated netlist file name can be configured with a prefix taken from the `file_name` parameter, and contains the number of the event the netlist was generated for.

The pixel address is used to identify the fired pixels in the netlist. If we consider the pixel (6,3) fired (7th column and 4th row) in a 10x10 matrix, the index 63 will be written in the netlist for this pixel (linearization of the 2D x and y indexes).

The pixel address is used to identify the fired pixels in the netlist, a linearization following

```math

i = x * N_y + y

```

is used. Here, `x` and `y` are the respective pixel coordinates and $`N_y`$ is the number of pixels along `y`.

This means that e.g. considering pixel (6,3) fired (7th column and 4th row) in a 10x10 matrix, the index 63 will be written in the netlist for this pixel..

The parameter `waveform_to_save` is used to write at the end of the generated netlist the waveform(s) to be saved (always using the index notation to identify the fired pixels).

The electrical circuit simulation can be performed within the Allpix Squared event using the parameter `simulator_command` which is used to specify the command line to execut. Not setting it switches the feature off, setting a value will enable it. The generated netlist name to execute is appended at the end of the command, as illustrated below for `SPECTRE` syntax:

The electrical circuit simulation can be performed within the Allpix Squared event using the parameter `simulator_command` which is used to specify the command line to execute. Not setting it switches the feature off, setting a value will enable it. The generated netlist name to execute is appended at the end of the command, as illustrated below for `SPECTRE` syntax:

```shell

spectre -f nutascii <file_name_event1.scs>

* `target`: Syntax for the additional data to be written in the netlist, either `SPECTRE` or `SPICE`.

* `netlist_template`: Location of file containing the netlist template of the circuit in one of the supported formats.

* `file_name` : Generated netlist prefix name (the suffix is the event number).

* `source_type`: Type of current source to be used, `ISOURCE` and `ISOURCE_PULSE`.

* `file_name` : Generated netlist prefix name to which the event number is added as suffix. Defaults to `output_netlist_event_`.

* `source_type`: Type of current source to be used, `ISOURCE` and `ISOURCE_PULSE`. Defaults to `ISOURCE_PULSE`.

* `source_name`: Name of the current source instance in the netlist.

* `subckt_name`: Name of the circuit the source is connected to.

* `common_nets`: Nets shared between the pixels.

* `t_delay`: delay from 0 before the current pulse starts, default to 0 ns

* `t_rise`: rise time of the current pulse, default to 1 ns, only works for the `ISOURCE_PULSE`

* `t_width`: width of the current pulse, default to 3 ns, only works for the `ISOURCE_PULSE`

* `t_fall`: fall time of the current pulse, default to 1 ns, only works for the `ISOURCE_PULSE`

* `t_delay`: delay from 0 before the current pulse starts, defaults to 0 ns

* `t_rise`: rise time of the current pulse, defaults to 1 ns, only works for the `ISOURCE_PULSE`

* `t_width`: width of the current pulse, defaults to 3 ns, only works for the `ISOURCE_PULSE`

* `t_fall`: fall time of the current pulse, defaults to 1 ns, only works for the `ISOURCE_PULSE`

* `waveform_to_save`: Name of the waveforms to save

* `simulator_command`: If specified, launches the electrical simulation. Command to be exuted in the terminal, the generated netlist name is appended at the end of the command.

* `simulator_command`: If specified, launches the electrical simulation. Command to be executed in the terminal, the generated netlist name is appended at the end of the command.

## Usage