speed vs numpy
```nim
import nimpy
import times
import arraymancer

var 
  tic, toc: float

# for math
let np = pyImport("numpy")
tic = cpuTime()
for i in 0..<200:
  discard np.sqrt(np.cos(np.sin(np.linspace(0, 10, 1000))))
toc = cpuTime()
echo "np time: ", toc - tic

tic = cpuTime()
for i in 0..<200:
  discard sqrt(cos(sin(arraymancer.linspace(0, 10, 1000))))
toc = cpuTime()
echo "arraymancer time: ", toc - tic
```

Shell and output:
```bash
 nim c -r npy                                                     
Hint: used config file '/home/neo/.choosenim/toolchains/nim-1.4.8/config/nim.cfg' [Conf]
Hint: used config file '/home/neo/.choosenim/toolchains/nim-1.4.8/config/config.nims' [Conf]
.................................................................................................................................................................................................................................CC: read
CC: write
CC: stdlib_times.nim
CC: stdlib_random.nim
CC: ../../../.nimble/pkgs/arraymancer-0.7.5/arraymancer/tensor/ufunc.nim
CC: npy.nim

Hint:  [Link]
Hint: 135625 lines; 1.764s; 180.102MiB peakmem; Debug build; proj: /home/neo/work/nim-projects/nim-learn/npy; out: /home/neo/work/nim-projects/nim-learn/npy [SuccessX]
Hint: /home/neo/work/nim-projects/nim-learn/npy  [Exec]
np time: 0.012997972
arraymancer time: 0.03080387
```

If it is compiled with release
```
nim c -r -d:release npy
```
I get time：
```bash
np time: 0.01219863
arraymancer time: 0.007503163999999993
```

Could I improve the speed further?