scipy.sparse.linalg._svdp signature mismatch

[lesteve]

🐛 Bug

To Reproduce

import numpy as np
from scipy.sparse.linalg._svdp import _svdp

np.random.seed(0)
n, k = 70, 10
A = np.random.random((n, n))
_svdp(A, k, kmax=5*k)

Stack-trace with debug symbols:

Uncaught RuntimeError: null function or function signature mismatch
    at dgetu0_ (00055cfe:0x9d7e)
    at dlanbpro_ (00055cfe:0xd2b2)
    at dlansvd_irl__ (00055cfe:0xa19e)
    at dynCall (pyodide.asm.js:16146:40)
    at pyodide.asm.js:16154:18
    at stubs.<computed> (pyodide.asm.js:16567:33)
    at f2py_rout__dpropack_dlansvd_irl (00055cfe:0x75a7)
    at fortran_call (0003e3ba:0x6642)
    at _PyObject_Call (pyodide.asm.wasm:0x131064)
    at PyObject_Call (pyodide.asm.wasm:0x13109d)

Debugging with Chromium, the function is called with 7 arguments with a i32 return type:

call_indirect (param i32 i32 i32 i32 i32 i32 i32) (result i32)

but wasm functions has 8 arguments and returns f32

(func $cb_daprod_in___user__routines (;111;) (param $var0 i32) (param $var1 i32) (param $var2 i32) (param $var3 i32) (param $var4 i32) (param $var5 i32) (param $var6 i32) (param $var7 i32) (result f32)

Not sure where this comes from ...

Expected behavior

No error

Environment

• Pyodide Version: both stable (0.21.3) and latest
• Browser version: not relevant
• Any other relevant information:

Additional context

Bumped into this when looking at scipy.sparse test suite issues in lesteve/scipy-tests-pyodide#3

[hoodmane]

Thanks for the report! Well the mismatch in the number of arguments is due to the extra ftnlen inserted by f2c. The following patch should fix it:

--- a/scipy/sparse/linalg/_propack/dpropack.pyf
+++ b/scipy/sparse/linalg/_propack/dpropack.pyf
@@ -3,7 +3,7 @@
 python module __user__routines
     interface
         function daprod(transa,m,n,x,y,dparm,iparm)
-           character*1 :: transa
+           integer :: transa
            integer intent(in) :: m
            integer intent(in) :: n
            double precision depend(m,n),check(len(x)>=(transa[0] == 'n' ? n : m)),dimension((transa[0] == 'n' ? n : m)) :: x

About the return type, I'm not sure yet.