When the error comes, how to return a flag but not stop the process

Sometimes when I use "vpainteral" for the integral of a piecewise function, it does not work, then will report an error and stop the process. I am wondering whether MATLAB can return a flag or some numbers but not stop my process, such that I can use the my-made method replace (much more time-consuming) to solve it at that time.

Thanks in advance.

[Walter Roberson]

Does vpaintegral() itself report an error? If so, what is the error?

Or is vpaintegral() just returning an unresolved vpaintegral() expression, and the rest of your code is not expecting that?

[博文 李]

"double(vpaintegral(INS_INX_CAP_FUN,T_MIN,T_MAX))" will be wrong with 

Error using symengine
Unable to convert expression containing remaining symbolic function calls into double array. Argument must be expression that evaluates to number.

Error in sym/double (line 800)
        Xstr = mupadmex('symobj::double', S.s, 0);


The INS_INX_CAP_FUN is a piecewise function as like

piecewise(mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416) in Dom::Interval([0], 1165313976553531/35184372088832) & (2896007884017551*2^(356569039086329/17179869184000000))/816205918912235008 - 2896007884017551/816205918912235008 < 1/(((3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 - (6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 + 996919633055797/1099511627776)^2 + ((2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 + (2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 - 3453068943317637/4398046511104)^2)^(3/4) & mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208) in Dom::Interval([0], 5588896607027279/17592186044416), (10000000*log(816205918912235008/(2896007884017551*(((3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 - (6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 + 996919633055797/1099511627776)^2 + ((2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 + (2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 - 3453068943317637/4398046511104)^2)^(3/4)) + 1))/log(2), mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416) in Dom::Interval([0], 1165313976553531/35184372088832) & (2896007884017551*2^(356569039086329/17179869184000000))/816205918912235008 - 2896007884017551/816205918912235008 < 1/(((2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 - (2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 + 25494418663792753114220555171887/9903520314283042199192993792)^2 + ((6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 + (3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 - 70315293125325115106280632402027/39614081257132168796771975168)^2)^(3/4) & mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208) in Dom::Interval([5588896607027279/17592186044416], 5588896607027279/8796093022208), (10000000*log(816205918912235008/(2896007884017551*(((2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 - (2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 + 25494418663792753114220555171887/9903520314283042199192993792)^2 + ((6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 + (3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 - 70315293125325115106280632402027/39614081257132168796771975168)^2)^(3/4)) + 1))/log(2), mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416) in Dom::Interval([1165313976553531/35184372088832], 1165313976553531/17592186044416) & mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208) in Dom::Interval([0], 5588896607027279/17592186044416) & (2896007884017551*2^(356569039086329/17179869184000000))/816205918912235008 - 2896007884017551/816205918912235008 < 1/(((6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 + (3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 - 5031852398038993589438635124927/9903520314283042199192993792)^2 + ((2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 - (2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 + 866923229301288165552489782879/4951760157141521099596496896)^2)^(3/4), (10000000*log(816205918912235008/(2896007884017551*(((6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 + (3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 - 5031852398038993589438635124927/9903520314283042199192993792)^2 + ((2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 - (2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 + 866923229301288165552489782879/4951760157141521099596496896)^2)^(3/4)) + 1))/log(2), mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416) in Dom::Interval([1165313976553531/35184372088832], 1165313976553531/17592186044416) & (2896007884017551*2^(356569039086329/17179869184000000))/816205918912235008 - 2896007884017551/816205918912235008 < 1/(((2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 + (2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 - 35003885125600300628797939856621/9903520314283042199192993792)^2 + ((6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 - (3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 + 14270068429581788942475215379823/39614081257132168796771975168)^2)^(3/4) & mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208) in Dom::Interval([5588896607027279/17592186044416], 5588896607027279/8796093022208), (10000000*log(816205918912235008/(2896007884017551*(((2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 + (2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 - 35003885125600300628797939856621/9903520314283042199192993792)^2 + ((6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 - (3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 + 14270068429581788942475215379823/39614081257132168796771975168)^2)^(3/4)) + 1))/log(2), mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416) in Dom::Interval([0], 1165313976553531/35184372088832) & 1/(((3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 - (6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 + 996919633055797/1099511627776)^2 + ((2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 + (2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 - 3453068943317637/4398046511104)^2)^(3/4) < (2896007884017551*2^(356569039086329/17179869184000000))/816205918912235008 - 2896007884017551/816205918912235008 & mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208) in Dom::Interval([0], 5588896607027279/17592186044416) | mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416) in Dom::Interval([1165313976553531/35184372088832], 1165313976553531/17592186044416) & mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208) in Dom::Interval([0], 5588896607027279/17592186044416) & 1/(((6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 + (3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 - 5031852398038993589438635124927/9903520314283042199192993792)^2 + ((2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 - (2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 + 866923229301288165552489782879/4951760157141521099596496896)^2)^(3/4) < (2896007884017551*2^(356569039086329/17179869184000000))/816205918912235008 - 2896007884017551/816205918912235008 | mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416) in Dom::Interval([1165313976553531/35184372088832], 1165313976553531/17592186044416) & 1/(((2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 + (2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 - 35003885125600300628797939856621/9903520314283042199192993792)^2 + ((6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 - (3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 + 14270068429581788942475215379823/39614081257132168796771975168)^2)^(3/4) < (2896007884017551*2^(356569039086329/17179869184000000))/816205918912235008 - 2896007884017551/816205918912235008 & mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208) in Dom::Interval([5588896607027279/17592186044416], 5588896607027279/8796093022208) | mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416) in Dom::Interval([0], 1165313976553531/35184372088832) & 1/(((2040108213996589*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/140737488355328 - (2976440700760609*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/562949953421312 + 25494418663792753114220555171887/9903520314283042199192993792)^2 + ((6011815895049549*mod(t + 3262727792551503/140737488355328, 1165313976553531/17592186044416))/281474976710656 + (3077304917261093*mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208))/2251799813685248 - 70315293125325115106280632402027/39614081257132168796771975168)^2)^(3/4) < (2896007884017551*2^(356569039086329/17179869184000000))/816205918912235008 - 2896007884017551/816205918912235008 & mod(t + 5613126887686237/35184372088832, 5588896607027279/8796093022208) in Dom::Interval([5588896607027279/17592186044416], 5588896607027279/8796093022208), 0)

It's a lillte bit long, simply, it is:
"INS_INX_CAP_FUN = piecewise((CAP_FUN(t)>INS_CAP),        CAP_FUN(t), (CAP_FUN(t)<INS_CAP),   0);"
 
where CAP_FUN(t) is another piecewise function, and INS_CAP is a constant.

By the way, when INS_CAP is set some other numbers around the number error occures, the process is work, that is 
"double(vpaintegral(INS_INX_CAP_FUN,T_MIN,T_MAX))" is work.

Answer 1

[Bruno Luong]

You might learn about

try / catch

[博文 李]

Thanks for your suggestions. It's quite helpful.