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Subs function invalid operand message

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or ohev shalom
or ohev shalom 2019-3-12
编辑： madhan ravi 2019-3-12
Hello all,
I'm trying to evaluate several boolean expressions which involves symbolic variables D and R.
When I try to evaluate
f3 = ~R & ~D
R = 0; D = 0;
subs(f3)
ans =
~0
it works fine.
But for some reason, several expressions occur "Invalid operand" error message.
For example:
f3 = ~D & R
R = 0; D = 0;
subs(f3)
Error using symengine
Invalid operand.
Error in sym/subs>mupadsubs (line 160)
G = mupadmex('symobj::fullsubs',F.s,X2,Y2);
Error in sym/subs (line 145)
G = mupadsubs(F,X,Y);
However, if I try to evaluate the expression above without symbolic variables:
~0 & 0
ans =
logical
0
it works perfectly.
Any suggestions how to solve this issue?
Thanks in advance.
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madhan ravi
madhan ravi 2019-3-12
编辑：madhan ravi 2019-3-12
What does the below show? , when you type it in command window
whos R
whos D
or ohev shalom
or ohev shalom 2019-3-12
Correction:
If R and D are symbolic then
subs(f3,{R,D},{0,0})
gives the same error.
If R and D are changed to logical\double (after building the expression) then I get
temp = subs(f3,{R,D},{0,0})
temp =
~D & R

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