Vsub=V.subs(-(2 - x**4)**(3/2)/6,0)
print('The volume when x=0 is',Vsub)
Name error: name 'V' is not defined
In an isympy session,
In [114]: V = sympify('-(2-x**4)**(3/2)')
In [115]: V
Out[115]:
3/2
⎛ 4⎞
-⎝2 - x ⎠
In [116]: V.subs({x:0})
Out[116]: -2⋅√2
Related
I have my function:
function [result] = my_func(x,y)
result = y^2*(1-3*x)-3*y;
endfunction
Also, my vector with Ts, my function address and my initial variable x_0
load file_with_ts
# Add my limits as I also want to calculate those
# (all values in file_with_ts are within those limits.)
t_points = [-1, file_with_ts, 2]
myfunc = str2func("my_func")
x_0 = 0.9142
I am trying to execute the following line:
lsode_d1 = lsode(myfunc, x_0, t_points)
And expecting a result, but getting the following error:
INTDY-- T (=R1) ILLEGAL
In above message, R1 = 0.7987082301475D+00
T NOT IN INTERVAL TCUR - HU (= R1) TO TCUR (=R2)
In above, R1 = 0.8091168896311D+00 R2 = 0.8280400838323D+00
LSODE-- TROUBLE FROM INTDY. ITASK = I1, TOUT = R1
In above message, I1 = 1
In above message, R1 = 0.7987082301475D+00
error: lsode: invalid input detected (see printed message)
error: called from
main at line 20 column 10
Also, the variable sizes are:
x_0 -> 1x1
t_points -> 1x153
myfunc -> 1x1
I tried transposing the t_points vector
using #my_func instead of the str2func function
I tried adding multiple variables as the starting point (instead of x_0 I entered [x_0; x_1])
Tried changing my function header from my_func(x, y) to my_func(y, x)
Read the documentation and confirmed that my_func allows x to be a vector and returns a vector (whenever x is a vector).
EDIT: T points is the following 1x153 matrix (with -1 and 2 added to the beggining and the end respectively):
-4.9451e-01
-4.9139e-01
-4.7649e-01
-4.8026e-01
-4.6177e-01
-4.5412e-01
-4.4789e-01
-4.2746e-01
-4.1859e-01
-4.0983e-01
-4.0667e-01
-3.8436e-01
-3.7825e-01
-3.7150e-01
-3.5989e-01
-3.5131e-01
-3.4875e-01
-3.3143e-01
-3.2416e-01
-3.1490e-01
-3.0578e-01
-2.9267e-01
-2.9001e-01
-2.6518e-01
-2.5740e-01
-2.5010e-01
-2.4017e-01
-2.3399e-01
-2.1491e-01
-2.1067e-01
-2.0357e-01
-1.8324e-01
-1.8112e-01
-1.7295e-01
-1.6147e-01
-1.5424e-01
-1.4560e-01
-1.1737e-01
-1.1172e-01
-1.0846e-01
-1.0629e-01
-9.4327e-02
-8.0883e-02
-6.6043e-02
-6.6660e-02
-6.1649e-02
-4.7245e-02
-2.8332e-02
-1.8043e-02
-7.7416e-03
-6.5142e-04
1.0918e-02
1.7619e-02
3.4310e-02
3.3192e-02
5.2275e-02
5.5756e-02
6.8326e-02
8.2764e-02
9.5195e-02
9.4412e-02
1.1630e-01
1.2330e-01
1.2966e-01
1.3902e-01
1.4891e-01
1.5848e-01
1.7012e-01
1.8026e-01
1.9413e-01
2.0763e-01
2.1233e-01
2.1895e-01
2.3313e-01
2.4092e-01
2.4485e-01
2.6475e-01
2.7154e-01
2.8068e-01
2.9258e-01
3.0131e-01
3.0529e-01
3.1919e-01
3.2927e-01
3.3734e-01
3.5841e-01
3.5562e-01
3.6758e-01
3.7644e-01
3.8413e-01
3.9904e-01
4.0863e-01
4.2765e-01
4.2875e-01
4.3468e-01
4.5802e-01
4.6617e-01
4.6885e-01
4.7247e-01
4.8778e-01
4.9922e-01
5.1138e-01
5.1869e-01
5.3222e-01
5.4196e-01
5.4375e-01
5.5526e-01
5.6629e-01
5.7746e-01
5.8840e-01
6.0006e-01
5.9485e-01
6.1771e-01
6.3621e-01
6.3467e-01
6.5467e-01
6.6175e-01
6.6985e-01
6.8091e-01
6.8217e-01
6.9958e-01
7.1802e-01
7.2049e-01
7.3021e-01
7.3633e-01
7.4985e-01
7.6116e-01
7.7213e-01
7.7814e-01
7.8882e-01
8.1012e-01
7.9871e-01
8.3115e-01
8.3169e-01
8.4500e-01
8.4168e-01
8.5705e-01
8.6861e-01
8.8211e-01
8.8165e-01
9.0236e-01
9.0394e-01
9.2033e-01
9.3326e-01
9.4164e-01
9.5541e-01
9.6503e-01
9.6675e-01
9.8129e-01
9.8528e-01
9.9339e-01
Credits to Lutz Lehmann and PierU.
The problem lied in the array t_points not being a monotonous array. Adding a sort(t_points) before doing any calculations fixed the error.
I'm still not very familiar with numba and my problem is that I have the piece of code bellow that I use for randomize the edges of graphs.
This code is simply used to swap some edges in a connectivity matrix given the number of desired swaps and a seed for the random number generator.
My problem is that when I try to use it with numba to speed it up I did not menage to run it. The error it returns is also pasted bellow.
#nb.jit(nopython=True)
def _randomize_adjacency_wei(A, n_swaps, seed):
np.random.seed(seed)
# Number of nodes
n_nodes = A.shape[0]
# Copy the adj. matrix
Arnd = A.copy()
# Choose edges that will be swaped
edges = np.random.choice(n_nodes, size=(4, n_swaps), replace=True).T
#itr = range(n_swaps)
#for it in tqdm(itr) if verbose else itr:
it = 0
for it in range(n_swaps):
i,j,k,l = edges[it,:]
if len(np.unique([i,j,k,l]))<4:
continue
else:
# Old values of weigths
w_ij,w_il,w_kj,w_kl=Arnd[i,j],Arnd[i,l],Arnd[k,j],Arnd[k,l]
# Swaping edges
Arnd[i,j]=Arnd[j,i]=w_il
Arnd[k,l]=Arnd[l,k]=w_kj
Arnd[i,l]=Arnd[l,i]=w_ij
Arnd[k,j]=Arnd[j,k]=w_kl
return Arnd
TypingError: Failed in nopython mode pipeline (step: nopython frontend)
No implementation of function Function(<function unique at 0x7f1a1c03b0d0>) found for signature:
>>> unique(list(int64)<iv=None>)
There are 2 candidate implementations:
- Of which 2 did not match due to:
Overload in function 'np_unique': File: numba/np/arrayobj.py: Line 1915.
With argument(s): '(list(int64)<iv=None>)':
Rejected as the implementation raised a specific error:
TypingError: Failed in nopython mode pipeline (step: nopython frontend)
Unknown attribute 'ravel' of type list(int64)<iv=None>
File "../../../home/vinicius/anaconda3/lib/python3.8/site-packages/numba/np/arrayobj.py", line 1918:
def np_unique_impl(a):
b = np.sort(a.ravel())
^
During: typing of get attribute at /home/vinicius/anaconda3/lib/python3.8/site-packages/numba/np/arrayobj.py (1918)
File "../../../home/vinicius/anaconda3/lib/python3.8/site-packages/numba/np/arrayobj.py", line 1918:
def np_unique_impl(a):
b = np.sort(a.ravel())
^
raised from /home/vinicius/anaconda3/lib/python3.8/site-packages/numba/core/typeinfer.py:1071
During: resolving callee type: Function(<function unique at 0x7f1a1c03b0d0>)
During: typing of call at <ipython-input-165-90ffd30fe0e8> (19)
File "<ipython-input-165-90ffd30fe0e8>", line 19:
def _randomize_adjacency_wei(A, n_swaps, seed):
<source elided>
i,j,k,l = edges[it,:]
if len(np.unique([i,j,k,l]))<4:
^
Thanks in advance,
Vinicius
According to the comments, you are passing a list to np.unique() but this is not supported by Numba.
Modifying the code this way:
i, j, k, l = e = edges[it, :]
if len(np.unique(e)) < 4:
...
The following example doesn't produce any errors:
>>> A = np.random.randint(0, 5, (8,8))
>>> r = _randomize_adjacency_wei(A, 4, 33)
I am writing this F90 program to compute a function in fortran which takes the input from a .mat file and save the results in another .mat file.
I followed this answer to get the code compiled and correctly linked. This is my makefile command:
gfortran -g -fcheck=all binhkorn_mat.F90 -I/usr/local/MATLAB/R2015b/extern/include/ -L/usr/local/MATLAB/R2015b/bin/glnxa64 -cpp -o binhkorn_mat -lmat -lmx -Wl,-rpath /usr/local/MATLAB/R2015b/bin/glnxa64/
The output file is apparently correctly compiled, but then once I run the program the following SF appears (I'm working on LINUX Ubuntu 14.04 LTS):
Program received signal SIGSEGV: Segmentation fault - invalid memory reference.
Backtrace for this error:
#0 0x7FD650063F27
#1 0x7FD6500644F4
#2 0x7FD64FCBCD3F
#3 0x7FD64FDD7AF6
#4 0x400A3F in binhkorn_mat at binhkorn_mat.F90:17 (discriminator 2)
./binhkorn_mat: Segmentation fault
I can't figure out if there's an error with the compiler or if I did something wrong with the pointers/functions definitions. Here's the code (binhkorn_mat.F90):
#include "fintrf.h"
PROGRAM binhkorn_mat
IMPLICIT NONE
mwPointer matOpen, matGetVariable, matPutVariable
mwPointer mpin, mpX, mpout, mpcf
INTEGER :: i,j
REAL*8, DIMENSION(2) :: x
REAL*8, DIMENSION(4) :: cf
!input/output through .mat f
mpin = matOpen('X.mat', 'u')
mpX = matGetVariable(mpin, 'X')
CALL mxCopyPtrToReal8(mpX, x, 2)
CALL matClose(mpin)
!fitness functions
cf(1) = ((x(1)-2)**2 + (x(2)-1)**2 + 2)
cf(2) = (9*x(1) + (x(2)-1)**2)
!constraints
cf(3) = x(1)*x(1) + x(2)*x(2) - 225
cf(4) = x(1) - 3*x(2) + 10
!output file created
CALL mxCopyReal8ToPtr(cf, mpcf, 4)
mpout = matOpen('cf.mat', 'w')
mpcf = matPutVariable(mpout, 'cf', mpcf)
CALL matClose(mpout)
END PROGRAM
The X.mat file is correctly created by an external Matlab script and contains a variable named X which is a 2-element row vector.
I basically misunderstood how to use of many functions. The pointers i supplied as input to some of them were not the correct ones. I post here the working solution:
#include "fintrf.h"
PROGRAM binhkorn_mat
IMPLICIT NONE
mwPointer matOpen, matGetVariable!, matPutVariable
mwPointer mxGetData, mxGetNumberOfElements, mxCreateNumericArray
mwPointer mpin, mpX, mpout, mpcf
mwSize ndim
mwSize dims(2)
INTEGER :: s
INTEGER*4 mxClassIDFromClassName
CHARACTER (LEN = 6) :: classname
REAL*8, DIMENSION(2) :: x
REAL*8, DIMENSION(4) :: cf
!input/output through .mat f
mpin = matOpen('X.mat', 'r')
mpX = matGetVariable(mpin, 'X')
CALL mxCopyPtrToReal8(mxGetData(mpX), x, mxGetNumberOfElements(mpX))
!CALL matClose(mpin)
!fitness functions
cf(1) = ((x(1)-2)**2 + (x(2)-1)**2 + 2)
cf(2) = (9*x(1) + (x(2)-1)**2)
!constraints
cf(3) = x(1)*x(1) + x(2)*x(2) - 225
cf(4) = x(1) - 3*x(2) + 10
!output .mat file created and filled
s = size(cf)
ndim = 2
classname = 'double'
dims(1) = 1
dims(2) = s
mpcf = mxCreateNumericArray(ndim, dims, mxClassIDFromClassName(classname), 0)
CALL mxCopyReal8ToPtr(cf, mxGetData(mpcf), mxGetNumberOfElements(mpcf))
mpout = matOpen('cf.mat', 'w')
CALL matPutVariable(mpout, 'cf', mpcf)
!CALL matClose(mpout)
END PROGRAM
I have a problem with the following source. When it is compiled in gfortran, it does not work properly and then two error message showed up.
How do I solve this problem?
Any comment would be very helpful.
Thanks in advance.
program driver
integer i,ln,n,e,count,x,a,b,total
character driverid*12,var*12,ch*12
parameter (n=720321)
c parameter (n=55062)
dimension var(n),a(n),b(n)
write(*,*) 'input run id(text)'
read(*,55) driverid
55 format(a)
ln=index(driverid,' ')-1
open(6,file=driverid(1:ln)//'.out',form='formatted'
+,status='unknown')
open(1,file=driverid(1:ln)//'.txt',status='old')
do i=1,2
read(1,*)
end do
read(1,*) (var(i),i=1,n)
close(1)
total=0
count=1
do i=1,n
b(i)=0
read(var(i),*,iostat=e) x
if (e .eq. 0) then
a(count)=x
count=count+1
else
ln=index(var(i),' ')-1
if (var(i)(ln-1:ln-1) .eq. 'r') then
var(i)=var(i)(1:ln-2)
else
var(i)=var(i)(1:ln-1)
end if
read(var(i),'(i)') b(count-1)
end if
end do
do i=1,count
total=total+1+b(i)
end do
do i=1,total
write(6,'(10i)') (a(i),j=1,b(i))
end do
close(6)
end
Error message is following as
$ gfortran driver.f
driver.f:43.23:
read(var(i),'(i)') b(count-1)
1
Error: Nonnegative width required in format string at (1)
driver.f:53.20:
write(6,'(10i)') (a(i),j=1,b(i))
1
Error: Nonnegative width required in format string at (1)
When specifying a format for an integer, you must specify the field width. If you want to have it flexible, you can set it to zero:
write(6, "(10I0)") ...
In Matlab, I have a IDPOLY object which I wish to "present" and store the resulting text in a text file.
eg if a is an IDPOLY object and I do
>> present(a)
I get
Discrete-time IDPOLY model: A(q)y(t) = B(q)u(t) + e(t)
A(q) = 1 - 1.31 q^-1 + 0.2425 q^-2 - 0.431 q^-3 + 0.4987 q^-4
B1(q) = 0.01357 + 0.04006 q^-1 - 0.04489 q^-2 + 0.007757 q^-3
- 0.1761 q^-4 + 0.06396 q^-5 - 0.2874 q^-6 + 0.3835 q^-7
B2(q) = -0.006397
Estimated using ARX with focus on data set iddata_est_shift
Loss function 0.0617185 and FPE 0.061879
Sampling interval: 0.025
Created: 24-Nov-2010 13:05:10
Last modified: 24-Nov-2010 13:06:56
Does anyone know how to capture this text as I'd like to write it to a text file in a log file. There are no returned arguments from present.
You can try using the diary command.
I've found the evalc() command which does exactly what I need.
evalc
Evaluate MATLAB expression with capture
Syntax
T = evalc(S)
[T, X, Y, Z, ...] = evalc(S)
and pass the expression as a string.