Add command 'pyplot', invoking numpy/matplotlib plotting,

similar to 'gnuplot' (Meisam Bahadori and Claude 4.8).
Commit contains Enhancements 94, 95, 98, 99, 182, 183.
Add a plotting flag 'boxesplot', in addition to 'combplot'
This fixes a bug in gnuplot and pyplot,
now offering both distinct combplot and boxesplot. (H. Vogt).

src/frontend/plotting/gnuplot.c

@@ -476,8 +476,10 @@ void ft_gnuplot(double *xlims, double *ylims,
         if(nolegend)
             fprintf(file, "set key off\n");
 
-        if (plottype == PLOT_COMB) {
+        if (plottype == PLOT_BOXES) {
             strcpy(plotstyle, "boxes");
+        } else if (plottype == PLOT_COMB) {
+            strcpy(plotstyle, "impulses");
         } else if (plottype == PLOT_POINT) {
             if (markers) {
                 // fprintf(file, "Markers: True\n");

src/frontend/plotting/plotit.c

@@ -633,6 +633,17 @@ bool plotit(wordlist *wl, const char *hcopy, const char *devname)
             pfound = TRUE;
         }
     }
+    if (getflag(wl, "boxesplot")) {
+        if (pfound) {
+            fprintf(cp_err,
+                "Warning: too many plot types given. "
+                "\"combplot\" is ignored.\n");
+        }
+        else {
+            ptype = PLOT_BOXES;
+            pfound = TRUE;
+        }
+    }
     if (getflag(wl, "pointplot")) {
         if (pfound) {
             fprintf(cp_err,

src/frontend/plotting/pvec.c

@@ -63,6 +63,10 @@ pvec(struct dvec *d)
         strcat(buf, ", plot = comb");
         break;
 
+    case PLOT_BOXES:
+        strcat(buf, ", plot = boxes");
+        break;
+
     case PLOT_POINT:
         strcat(buf, ", plot = point");
         break;

src/frontend/plotting/pyplot.c

@@ -0,0 +1,329 @@
+/**********
+ * Enhancement-94: matplotlib ("pyplot") plots.
+ *
+ * A backend for `plotit()` that mirrors the gnuplot backend (`gnuplot.c`):
+ * it writes the selected vectors to a `<file>.data` table and a `<file>.py`
+ * matplotlib script, then shells out to Python. Modelled on ft_gnuplot().
+**********/
+
+#include "ngspice/ngspice.h"
+#include "ngspice/cpdefs.h"
+#include "ngspice/ftedefs.h"
+#include "ngspice/dvec.h"
+#include "ngspice/fteparse.h"
+#include "pyplot.h"
+#if defined(__MINGW32__) || defined(_MSC_VER)
+#include <windows.h>
+#else
+#include <unistd.h>
+#endif
+#include <locale.h>
+
+#define PY_MAXVECTORS 64
+
+
+/* Write `s` as a single-quoted Python string literal, escaping backslashes
+   and single quotes. */
+static void
+quote_python_string(FILE *stream, const char *s)
+{
+    fputc('\'', stream);
+    for (; s && *s; s++) {
+        if (*s == '\\' || *s == '\'')
+            fputc('\\', stream);
+        fputc(*s, stream);
+    }
+    fputc('\'', stream);
+}
+
+
+void ft_pyplot(double *xlims, double *ylims,
+        double xdel, double ydel,
+        const char *filename, const char *title,
+        const char *xlabel, const char *ylabel,
+        GRIDTYPE gridtype, PLOTTYPE plottype,
+        struct dvec *vecs)
+{
+    FILE *file, *file_data;
+    struct dvec *v, *scale = NULL;
+    int i, col, numVecs, err, nper, nrows, row;
+    bool xlog, ylog, nogrid, markers, boxes, impulses, have_style, have_figsize;
+    char pointstyle[BSIZE_SP], terminal[BSIZE_SP], python[BSIZE_SP], style[BSIZE_SP];
+    char figsize[BSIZE_SP], fmt[16];
+    char lwarg[32];         /* Enhancement-183: "linewidth=%g, " or "" */
+    double linewidth = 0.0;
+    char backend[BSIZE_SP]; /* Enhancement-183: matplotlib backend override */
+    bool have_backend;
+    /* Enhancement-183: hold a full directory path (the deck's folder) + base
+       name, not just a bare "pyplot.data" -- 128 was too small for a path. */
+    char filename_data[1024], filename_py[1024];
+    char buf[2 * 1024 + BSIZE_SP];
+    char *text;
+    double figw = 0.0, figh = 0.0;
+    bool hardcopy = FALSE;
+
+    NG_IGNORE(xdel);
+    NG_IGNORE(ydel);
+
+#ifdef SHARED_MODULE
+    char *llocale = setlocale(LC_NUMERIC, NULL);
+    setlocale(LC_NUMERIC, "C");
+#endif
+
+    snprintf(filename_data, sizeof(filename_data), "%s.data", filename);
+    snprintf(filename_py, sizeof(filename_py), "%s.py", filename);
+
+    for (v = vecs, numVecs = 0; v; v = v->v_link2)
+        numVecs++;
+
+    if (numVecs == 0) {
+        return;
+    } else if (numVecs > PY_MAXVECTORS) {
+        fprintf(cp_err, "Error: too many vectors for pyplot.\n");
+        return;
+    }
+
+    /* `set pyplot_terminal=png|svg|pdf` -> render headless (Agg) to
+       <file>.<fmt> rather than opening an interactive window. Enhancement-99
+       adds the svg and pdf vector formats alongside png. */
+    fmt[0] = '\0';
+    if (cp_getvar("pyplot_terminal", CP_STRING, terminal, sizeof(terminal))) {
+        if (cieq(terminal, "png") || cieq(terminal, "png/quit")) {
+            strcpy(fmt, "png");
+            hardcopy = TRUE;
+        } else if (cieq(terminal, "svg") || cieq(terminal, "svg/quit")) {
+            strcpy(fmt, "svg");
+            hardcopy = TRUE;
+        } else if (cieq(terminal, "pdf") || cieq(terminal, "pdf/quit")) {
+            strcpy(fmt, "pdf");
+            hardcopy = TRUE;
+        }
+    }
+
+    /* Enhancement-99: `set pyplot_figsize=W,H` -> figure size in inches. */
+    have_figsize = FALSE;
+    if (cp_getvar("pyplot_figsize", CP_STRING, figsize, sizeof(figsize))) {
+        if (sscanf(figsize, "%lf%*[ ,xX]%lf", &figw, &figh) == 2
+                && figw > 0.0 && figh > 0.0)
+            have_figsize = TRUE;
+    }
+
+    /* the Python interpreter, overridable with `set pyplot_python=...`. */
+    if (!cp_getvar("pyplot_python", CP_STRING, python, sizeof(python)))
+        strcpy(python, "python3");
+
+    /* Enhancement-183: `set pyplot_backend=<name>` -> select the matplotlib
+       backend explicitly (e.g. TkAgg, QtAgg, MacOSX, WebAgg, Agg). Overrides
+       the automatic backend, including the 'Agg' otherwise forced for the
+       png/svg/pdf terminals -- so it is the user's responsibility to pick a
+       file-capable/headless backend when combining it with those. */
+    have_backend = cp_getvar("pyplot_backend", CP_STRING, backend, sizeof(backend))
+                   ? TRUE : FALSE;
+
+    /* Enhancement-98: `set pyplot_subplots=N` -> stacked subplots sharing the
+       x-axis, N traces per panel (0/unset = a single axis, as before). */
+    if (!cp_getvar("pyplot_subplots", CP_NUM, &nper, 0))
+        nper = 0;
+    if (nper < 0)
+        nper = 0;
+    nrows = (nper > 0) ? ((numVecs + nper - 1) / nper) : 1;
+
+    /* Enhancement-98: `set pyplot_style=<name>` -> a matplotlib style sheet
+       (e.g. dark, ggplot, bmh). "dark" aliases matplotlib's dark_background. */
+    have_style = cp_getvar("pyplot_style", CP_STRING, style, sizeof(style)) ? TRUE : FALSE;
+    if (have_style && cieq(style, "dark"))
+        strcpy(style, "dark_background");
+
+    /* Enhancement-183: `set pyplot_linewidth=<w>` -> matplotlib line width (in
+       points) applied to every trace; unset/<=0 leaves matplotlib's default. */
+    lwarg[0] = '\0';
+    if (cp_getvar("pyplot_linewidth", CP_REAL, &linewidth, 0) && linewidth > 0.0)
+        (void) snprintf(lwarg, sizeof lwarg, "linewidth=%g, ", linewidth);
+
+    markers = FALSE;
+    if (cp_getvar("pointstyle", CP_STRING, pointstyle, sizeof(pointstyle)))
+        if (cieq(pointstyle, "markers"))
+            markers = TRUE;
+
+    impulses = (plottype == PLOT_COMB);
+    boxes = (plottype == PLOT_BOXES);
+    if (plottype == PLOT_POINT)
+        markers = TRUE;
+
+    switch (gridtype) {
+    case GRID_LIN:
+        nogrid = xlog = ylog = FALSE;
+        break;
+    case GRID_XLOG:
+        xlog = TRUE;
+        nogrid = ylog = FALSE;
+        break;
+    case GRID_YLOG:
+        ylog = TRUE;
+        nogrid = xlog = FALSE;
+        break;
+    case GRID_LOGLOG:
+        xlog = ylog = TRUE;
+        nogrid = FALSE;
+        break;
+    case GRID_NONE:
+        nogrid = TRUE;
+        xlog = ylog = FALSE;
+        break;
+    default:
+        fprintf(cp_err, "Error: grid type unsupported by pyplot.\n");
+        return;
+    }
+
+    /* Write the data table: for each row, an (x, y) pair per vector, taken
+       from each vector's own scale (real part for complex data). */
+    if ((file_data = fopen(filename_data, "w")) == NULL) {
+        perror(filename);
+        return;
+    }
+    scale = vecs->v_scale;
+    for (i = 0; i < scale->v_length; i++) {
+        for (v = vecs; v; v = v->v_link2) {
+            struct dvec *sc = v->v_scale;
+            double xval = (i < sc->v_length)
+                ? (isreal(sc) ? sc->v_realdata[i] : realpart(sc->v_compdata[i]))
+                : NAN;
+            double yval = (i < v->v_length)
+                ? (isreal(v) ? v->v_realdata[i] : realpart(v->v_compdata[i]))
+                : NAN;
+            fprintf(file_data, "%e %e ", xval, yval);
+        }
+        fprintf(file_data, "\n");
+    }
+    (void) fclose(file_data);
+
+    /* Write the matplotlib script. */
+    if ((file = fopen(filename_py, "w")) == NULL) {
+        perror(filename);
+        return;
+    }
+    fprintf(file, "#!/usr/bin/env python3\n");
+    fprintf(file, "# generated by ngspice 'pyplot' (Enhancement-94)\n");
+    fprintf(file, "import numpy as np\n");
+    /* Enhancement-183: an explicit `pyplot_backend` wins; otherwise the file
+       terminals render headless with Agg (unchanged). matplotlib.use() must
+       precede `import matplotlib.pyplot`. */
+    if (have_backend) {
+        fprintf(file, "import matplotlib\n");
+        fprintf(file, "matplotlib.use(");
+        quote_python_string(file, backend);
+        fprintf(file, ")\n");
+    } else if (hardcopy) {
+        fprintf(file, "import matplotlib\n");
+        fprintf(file, "matplotlib.use('Agg')\n");
+    }
+    fprintf(file, "import matplotlib.pyplot as plt\n");
+    /* Enhancement-98: apply a matplotlib style sheet if requested (ignore an
+       unknown name rather than aborting the plot). */
+    if (have_style) {
+        fprintf(file, "try:\n    plt.style.use(");
+        quote_python_string(file, style);
+        fprintf(file, ")\nexcept Exception:\n    pass\n");
+    }
+    fprintf(file, "d = np.loadtxt(");
+    quote_python_string(file, filename_data);
+    fprintf(file, ")\n");
+    fprintf(file, "if d.ndim == 1:\n    d = d.reshape(-1, %d)\n", 2 * numVecs);
+    /* Enhancement-98: one axis, or `nrows` stacked subplots sharing the x-axis.
+       `axes` is always a 2-D array (squeeze=False) so it is indexed uniformly. */
+    if (have_figsize)
+        fprintf(file,
+                "fig, axes = plt.subplots(%d, 1, sharex=True, squeeze=False, "
+                "figsize=(%g, %g))\n", nrows, figw, figh);
+    else
+        fprintf(file, "fig, axes = plt.subplots(%d, 1, sharex=True, squeeze=False)\n", nrows);
+
+    col = 0;
+    row = 0;
+    i = 0;
+    for (v = vecs; v; v = v->v_link2) {
+        row = (nper > 0) ? (i / nper) : 0;
+        fprintf(file, "axes[%d, 0].", row);
+        if (boxes)
+            fprintf(file, "step(d[:, %d], d[:, %d], where='mid', %s", col, col + 1, lwarg);
+        else if (impulses)
+            fprintf(file, "stem(d[:, %d], d[:, %d], markerfmt=' ', %s", col, col + 1, lwarg);
+        else if (markers)
+            fprintf(file, "plot(d[:, %d], d[:, %d], marker='.', linestyle='None', ",
+                    col, col + 1);
+        else
+            fprintf(file, "plot(d[:, %d], d[:, %d], %s", col, col + 1, lwarg);
+        fprintf(file, "label=");
+        quote_python_string(file, v->v_name ? v->v_name : "");
+        fprintf(file, ")\n");
+        col += 2;
+        i++;
+    }
+
+    /* Per-axis cosmetics applied to every panel; the x-label goes on the
+       bottom panel only, the title becomes the figure suptitle. */
+    fprintf(file, "for _ax in axes[:, 0]:\n");
+    if (ylabel) {
+        text = cp_unquote(ylabel);
+        fprintf(file, "    _ax.set_ylabel(");
+        quote_python_string(file, text);
+        fprintf(file, ")\n");
+        tfree(text);
+    }
+    if (xlog)
+        fprintf(file, "    _ax.set_xscale('log')\n");
+    if (ylog)
+        fprintf(file, "    _ax.set_yscale('log')\n");
+    if (!nogrid)
+        fprintf(file, "    _ax.grid(True, which='both')\n");
+    if (xlims)
+        fprintf(file, "    _ax.set_xlim(%e, %e)\n", xlims[0], xlims[1]);
+    if (ylims && !ylog)
+        fprintf(file, "    _ax.set_ylim(%e, %e)\n", ylims[0], ylims[1]);
+    fprintf(file, "    _ax.legend()\n");
+    if (xlabel) {
+        text = cp_unquote(xlabel);
+        fprintf(file, "axes[-1, 0].set_xlabel(");
+        quote_python_string(file, text);
+        fprintf(file, ")\n");
+        tfree(text);
+    }
+    if (title) {
+        text = cp_unquote(title);
+        fprintf(file, "fig.suptitle(");
+        quote_python_string(file, text);
+        fprintf(file, ")\n");
+        tfree(text);
+    }
+    fprintf(file, "fig.tight_layout()\n");
+    if (hardcopy) {
+        fprintf(file, "fig.savefig(");
+        quote_python_string(file, filename);
+        fprintf(file, " + '.%s', dpi=100)\n", fmt);
+        fprintf(file, "print('pyplot: wrote %s.%s')\n", filename, fmt);
+    } else {
+        fprintf(file, "plt.show()\n");
+    }
+    (void) fclose(file);
+
+    /* Run it: synchronously for a PNG, in the background for a window. */
+#if defined(__MINGW32__) || defined(_MSC_VER)
+    if (hardcopy)
+        (void) snprintf(buf, sizeof(buf), "%s %s", python, filename_py);
+    else
+        (void) snprintf(buf, sizeof(buf), "start /B %s %s", python, filename_py);
+    _flushall();
+#else
+    if (hardcopy)
+        (void) snprintf(buf, sizeof(buf), "%s %s", python, filename_py);
+    else
+        (void) snprintf(buf, sizeof(buf), "%s %s &", python, filename_py);
+#endif
+    err = system(buf);
+    if (err == -1)
+        fprintf(cp_err, "Error: could not run '%s'.\n", buf);
+
+#ifdef SHARED_MODULE
+    setlocale(LC_NUMERIC, llocale);
+#endif
+}

src/frontend/plotting/pyplot.h

@@ -0,0 +1,15 @@
+/*************
+ * Header file for pyplot.c (Enhancement-94)
+ ************/
+
+#ifndef ngspice_PYPLOT_H
+#define ngspice_PYPLOT_H
+
+void ft_pyplot(double *xlims, double *ylims,
+        double xdel, double ydel,
+        const char *filename, const char *title,
+        const char *xlabel, const char *ylabel,
+        GRIDTYPE gridtype, PLOTTYPE plottype,
+        struct dvec *vecs);
+
+#endif

src/include/ngspice/dvec.h

@@ -24,7 +24,7 @@ enum dvec_flags {
 
 /* Plot types. */
 typedef enum {
-    PLOT_LIN, PLOT_COMB, PLOT_POINT, PLOT_RETLIN
+    PLOT_LIN, PLOT_COMB, PLOT_POINT, PLOT_RETLIN, PLOT_BOXES
 } PLOTTYPE;