Autoground fails with op-amps

[scottprahl]

The inverting amplifier that does not use autoground.

import lcapy
a = lcapy.Circuit("""
    E 1 0 opamp 3 2 Ad; right
    W 2 2_1; down
    R1 2_1 0_2 R1; down
    R2 2_1 1_1 R2; right
    W 1 1_1; down
    W 3_1 3_2; down
    Vs 3_2 0_3 Vs; down
    W 0_3 0_1; down
    W 3_1 3_3; right
    W 3_3 3; right
    W 1 12; right
    P 12 0; down
    W 0_1 0_2; right
    W 0_2 0; right
    ; label_nodes=True
""")
a[12].v

Consider the same circuit without separate ground nodes and with autoground=True. The following does not work .

import lcapy
a = lcapy.Circuit("""
    E 1 0 opamp 3 2 Ad; right
    W 2 2_1; down
    R1 2_1 0 R1; down
    R2 2_1 1_1 R2; right
    W 1 1_1; down
    W 3_1 3_2; down
    Vs 3_2 0 Vs; down
    W 3_1 3_3; right
    W 3_3 3; right
    W 1 12; right
    P 12 0; down
    ; label_nodes=True; autoground=True
""")
a.draw()

I suspect that op-amps were just overlooked when implementing autoground.

The following does at least draw the circuit,

a = lcapy.Circuit("""
    E 1 0_1 opamp 3 2 Ad; right
    W 2 2_1; down
    R1 2_1 0 R1; down
    R2 2_1 1_1 R2; right
    W 1 1_1; down
    W 3_1 3_2; down
    Vs 3_2 0 Vs; down
#    W 0_3 0_1; down
    W 3_1 3_3; right
    W 3_3 3; right
    W 1 12; right
    P 12 0; down
#    W 0_1 0_2; right
#    W 0_2 0; right
    ; label_nodes=True, autoground=True
""")
a.draw()

but, of course, a[12].v fails.

[mph-]

Thanks for the testcase. I've pushed a fix.

Note, there is a syntax error in your example.

; draw_nodes=True; autoground=True

should be

; draw_nodes=True, autoground=True

I'll see if I can make the parser more accommodating but am worried by unexpected consequences.

[scottprahl]

Confirmed that it works!

Oddly the semicolon error arose through copy-and-paste between Jupyter and the bug report :-)

Probably not worth making the parser more permissive :-)