Add command 'write_ic'

Write out the right hand side status of the matrix in format
    .ic = V(node_xx)
    This may be possible at the end of a simulation or after a 'stop'
    of the simulation, which may be resumed again afterwars. This
    status may be used to start another simulation with these
    parameters by inluding into the netlist.

src/frontend/com_wr_ic.c

@@ -0,0 +1,61 @@
+/* ngspice file
+   Copyright Holger Vogt 2021
+   License: BSD 3-clause 
+ */
+
+ /* Print the current node status to a file with format
+    .ic V(node) = value 
+ */
+
+#include "ngspice/ngspice.h"
+#include "ngspice/cpdefs.h"
+#include "ngspice/ftedefs.h"
+#include "ngspice/ftedev.h"
+#include "ngspice/ftedebug.h"
+#include "ngspice/cktdefs.h"
+
+ /* Print the current node status to a file with format
+    .ic V(node) = value 
+ */
+void
+com_wric(wordlist* wl) {
+
+    CKTnode* node;
+    CKTcircuit* ckt = NULL;
+    FILE* fp;
+    char* file;
+
+    if (wl)
+        file = wl->wl_word;
+    else
+        file = "dot_ic_out.txt";
+
+    if ((fp = fopen(file, "w")) == NULL) {
+        perror(file);
+        return;
+    }
+
+    if (!ft_curckt) {
+        fprintf(cp_err, "Error: there aren't any circuits loaded.\n");
+        return;
+    }
+    else if (ft_curckt->ci_ckt == NULL) { /* Set noparse? */
+        fprintf(cp_err, "Error: circuit not parsed.\n");
+        return;
+    }
+
+    ckt = ft_curckt->ci_ckt;
+
+    fprintf(fp, "* Intermediate Transient Solution\n");
+    fprintf(fp, "* Circuit: %s\n", ft_curckt->ci_name);
+    fprintf(fp, "* Recorded at simulation time: %g\n", ckt->CKTtime);
+    for (node = ckt->CKTnodes->next; node; node = node->next) {
+        if (!strstr(node->name, "#branch") && !strchr(node->name, '#'))
+            fprintf(fp, ".ic v(%s) = %g\n", node->name,
+                ckt->CKTrhsOld[node->number]);
+    }
+
+    fprintf(stdout, "\nNode data saved to file %s\n", file);
+
+    fclose(fp);
+}

src/frontend/com_wr_ic.h

@@ -0,0 +1,11 @@
+/* ngspice file
+   Copyright Holger Vogt 2021
+   License: BSD 3-clause 
+ */
+
+
+ /* Print the current node status to a file with format
+    .ic V(node) = value 
+ */
+extern void
+com_wric(wordlist* wl);