Found the following significant warnings:
  cor_struct.c:27:13: warning: using floating point absolute value function 'fabs' when argument is of integer type [-Wabsolute-value]
See '/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/fastmatrix.Rcheck/00install.out' for details.
Found the following math rendering problems:
helmert.Rd:16-22: Unknown column alignment: * in ...{\begin{array}{*{20}{c}}
      1/...
kronecker.prod.Rd:17-21: Unknown column alignment: * in ...{\begin{array}{*{20}{c}}
      x_...
Found the following math rendering problems:
helmert.Rd:16-22: Unknown column alignment: * in ...{\begin{array}{*{20}{c}}
      1/...
kronecker.prod.Rd:17-21: Unknown column alignment: * in ...{\begin{array}{*{20}{c}}
      x_...
Found the following significant warnings:
  cor_struct.c:27:13: warning: using floating point absolute value function 'fabs' when argument is of integer type [-Wabsolute-value]
See ‘/data/gannet/ripley/R/packages/tests-clang/fastmatrix.Rcheck/00install.out’ for details.
Found the following significant warnings:
  cor_struct.c:27:13: warning: using floating point absolute value function 'fabs' when argument is of integer type [-Wabsolute-value]
See ‘/Volumes/Builds/packages/big-sur-arm64/results/4.2/fastmatrix.Rcheck/00install.out’ for details.
Found the following significant warnings:
  cor_struct.c:27:13: warning: using floating point absolute value function 'fabs' when argument is of integer type [-Wabsolute-value]
  Warning: control reaches end of non-void function [-Wreturn-type]
See ‘/Volumes/Builds/packages/high-sierra-x86_64/results/4.2/fastmatrix.Rcheck/00install.out’ for details.
Found the following significant warnings:
  cor_struct.c:27:13: warning: using floating point absolute value function 'fabs' when argument is of integer type [-Wabsolute-value]
See ‘/Volumes/Builds/packages/big-sur-arm64/results/4.1/fastmatrix.Rcheck/00install.out’ for details.
Found the following significant warnings:
  cor_struct.c:27:13: warning: using floating point absolute value function 'fabs' when argument is of integer type [-Wabsolute-value]
  Warning: control reaches end of non-void function [-Wreturn-type]
See ‘/Volumes/Builds/packages/high-sierra-x86_64/results/4.1/fastmatrix.Rcheck/00install.out’ for details.