update README.md list of docs

Author: ahbarnett

README.md

@@ -38,13 +38,16 @@ If you prefer to read text files, the source to generate the above documentation
 - `docs/c_gpu.rst`   : documentation of C++/C function API for GPU library
 - `docs/opts.rst`    : optional parameters
 - `docs/error.rst`   : error codes
-- `docs/trouble.rst` : troubleshooting advice
+- `docs/trouble.rst` : troubleshooting and accuracy advice
+- `docs/performance.rst` : CPU timing benchmarks compared to older versions
 - `docs/tut.rst` and `tutorial/*` : tutorial application examples
 - `docs/fortran.rst` : usage examples from Fortran, documentation of interface
 - `docs/matlab.rst` and `docs/matlabhelp.raw` : using the MATLAB/Octave interface
 - `docs/python.rst` and `python/*/_interfaces.py` : using the Python interface
 - `docs/python_gpu.rst` : Python interface to GPU library
 - `docs/julia.rst`   : information for Julia users
+- `docs/nfft_migr.rst` and `docs/cufinufft_migration` : guides for migration
+- `docs/impl_gpu.rst`: implementation notes for GPU code
 - `docs/devnotes.rst`: notes/guide for developers
 - `docs/related.rst` : other recommended NUFFT packages
 - `docs/users.rst`   : some known users of FINUFFT, dependent packages

test/testutils.cpp

@@ -83,11 +83,11 @@ int main(int argc, char *argv[]) {
   }
   constexpr FLT EPSILON = std::numeric_limits<FLT>::epsilon();
   FLT relerr            = 2.0 * EPSILON; // 1 ULP, fine since 1.0 rep exactly
-  if (abs(infnorm(M, &a[0]) - 1.0) > relerr) return 1;
-  if (abs(twonorm(M, &a[0]) - sqrt((FLT)M)) > relerr * sqrt((FLT)M)) return 1;
+  if (std::abs(infnorm(M, &a[0]) - 1.0) > relerr) return 1;
+  if (std::abs(twonorm(M, &a[0]) - std::sqrt((FLT)M)) > relerr * std::sqrt((FLT)M)) return 1;
   b[0] = CPX(0.0, 0.0); // perturb b from a
-  if (abs(errtwonorm(M, &a[0], &b[0]) - 1.0) > relerr) return 1;
-  if (abs(sqrt((FLT)M) * relerrtwonorm(M, &a[0], &b[0]) - 1.0) > relerr) return 1;
+  if (std::abs(errtwonorm(M, &a[0], &b[0]) - 1.0) > relerr) return 1;
+  if (std::abs(std::sqrt((FLT)M) * relerrtwonorm(M, &a[0], &b[0]) - 1.0) > relerr) return 1;
 
 #ifdef SINGLE
   printf("testutilsf passed.\n");