Error in symengine for symbolic integration
12 次查看(过去 30 天)
显示 更早的评论
I want to calculate a symbolic integration like below:
syms z
hc=2.5e-9;
hp=1e-9;
e31=-2.2;
z1=z-hc-(hp/2);
z2=z+hc+(hp/2);
B31_1=double(int(e31*(pi/hp)*(sin(pi*z2/hp))*(z^1),'z',-hc-hp,-hc)+int(e31*(pi/hp)*(sin(pi*z1/hp))*(z^1),'z',hc,hc+hp));
But I get this error:
Error using symengine
Out of memory.
Error in sym/int (line 167)
rSym = mupadmex('symobj::intdef',f.s,x.s,a.s,b.s,options);
Note: For z^0 there is no error, but when z has power, this error appears.
What is solution for this? Thanks in advance.
4 个评论
Walter Roberson
2021-8-19
编辑:Walter Roberson
2021-8-19
On my system, in R2020a, it does not even use as much as 1 gigabyte between MATLAB itself and the MuPAD process to do the integration. No hint of a problem at all. MacOS.
采纳的回答
Wan Ji
2021-8-19
This is a bug in matlab. A good way to avoid this bug is just to predefine symbols rather than use constants in the symbolic process. When symbolic formula is derived, use subs and eval function to obtain the final results.
syms z hc hp e31
z1=z-hc-(hp/2);
z2=z+hc+(hp/2);
p = e31*(pi/hp)*(sin(pi*z2/hp))*z^1;
q = e31*(pi/hp)*(sin(pi*z1/hp))*z^1;
B31_1 = int(p,z,-hc-hp,-hc)+int(q,z,hc,hc+hp)
B31_1_val = eval(subs(B31_1,[hc,hp,e31],[2.5e-9, 1e-9, -2.2]))
The result in this
B31_1 =
(4*e31*hp)/pi
B31_1_val =
-2.801126998417358e-09
Since you observed this bug, I suggest you report it to MATHWORKS. You will be really appreciated. ovo
更多回答(0 个)
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Calculus 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!