[Pkg-electronics-devel] Bug#1120581: ngspice crashes in "tf" command if nodename is capitalised

[Siward de Groot]

Package: ngspice
Version: 44.2+ds-1
 
When i interactively issue a tf command and use a capitalised nodename,
ngspice crashes :
 
ngspice 67 -> tf v(Out,0) vin
Doing analysis at TEMP = 27.000000 and TNOM = 27.000000

Internal Error: incomplete CKTunsetup(), this will cause serious problems, please report this
issue !

ERROR: fatal error in ngspice, exit(1)


---
 
When same command is issued without capitalisation , it works :
siward at pc mailto:siward at pc:Spice$ ngspice try5
******
** ngspice-44.2 : Circuit level simulation program
** Compiled with KLU Direct Linear Solver
** The U. C. Berkeley CAD Group
** Copyright 1985-1994, Regents of the University of California.
** Copyright 2001-2024, The ngspice team.
** Please get your ngspice manual from https://ngspice.sourceforge.io/docs.html
** Please file your bug-reports at http://ngspice.sourceforge.net/bugrep.html
** Creation Date: Sun Jan 12 08:19:15 UTC 2025
******

Note: Compatibility modes selected: ps lt a


Circuit: * try5 : an rlc circuit

ngspice 64 -> tf v(out,0) vin
Doing analysis at TEMP = 27.000000 and TNOM = 27.000000

Using SPARSE 1.3 as Direct Linear Solver
Note: vin: dc value used for op instead of transient time=0 value.

No. of Data Rows : 1

---
 
I have tried this with that nodename in netlist file as "Out" and also as "out",
in both cases behaviour is same .
 
---
 
netlist file is :
* try5 : an RLC circuit
Vin in 0 dc 1 ac 1 pulse( 0 1 0 0 0 5 10)
R1 in rl 0.5
L1 rl Out 1
C1 Out co 1
Vco co 0 0
.end
* op
* print all
* ac dec 100 0.01 1
* plot real(out) im(out) mag(out)
* plot db(out)
* plot mag(out) mag( i(Vco) )
** that does not plot if nodenames are numeric , but it does if they are strings
** it only plots these if plot command is after ac command ,
** if i do pz command inbetween then it forgets ac values .
** "plot out" plots real part of voltage on out node .
* pz 1 0 out 0 vol pz
* print all
** that finds two poles , both at frequency 0.35
** peak output is at 0.2 Hz
* tran 0.01 10
* plot in out
** works
* tf v(out,0) Vin
** error
* tf v(out,0) vin
**
* ngspice 16 -> tf v(out,0) vin
* Doing analysis at TEMP = 27.000000 and TNOM = 27.000000
* Using SPARSE 1.3 as Direct Linear Solver
* Note: vin: dc value used for op instead of transient time=0 value.
* No. of Data Rows : 1
* ngspice 17 -> print all
* transfer_function = 1.000000e+00
* output_impedance_at_v(out,0) = 5.000000e-01
* vin#input_impedance = 1.000000e+20
 
---
I am using Debian stable , which i think is uptodate .
---
ngspice 65 -> sysinfo

OS: Linux version 6.12.48+deb13-amd64 (debian-kernel at lists.debian.org) (x86_64-linux-gnu-gcc-1
4 (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44) #1 SMP PREEMPT_DYNAMIC Deb
ian 6.12.48-1 (2025-09-20)

CPU: Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz
Physical processors: 1, Logical processors: 8
Total DRAM available = 7821.687500 MB.
DRAM currently available = 550.152344 MB.

---
 
Seems to me that this bug is related to uppercase/lowercase something,
that is to say : i really don't know much about spice ,
but it told me to report this , so i hope it helps .
 
Should you require me to run any testcode , or provide some other info , please send me an email .
 
with friendly greetings,
Siward de Groot
 
 
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