The best replacement for matlab is mathematica.

The best alternatives to matlab are rated as following:
★★★★★  mathematica
★★★★  r
★★★  scilab
★★★  python
★★★  julia
★★  maple
★★  octave
★★  mathcad
★★  c++
★★  operator
★★  labview
★  sas
★  java
★  and
★  fortran
★  excel
★  function
  java speed
  logical
  vba
  idl
  python speed
  stata
  fortran speed
  in if
  in if statement
  while
  scipy
  statements
  gauss
  matplotlib
  minitab
  simulink

Your alternative for matlab is not listed? Suggest!
Speaking about matlab, one probably shouldn't forget about simulink.

Other search terms related to matlab and their ratings are:
★★★★★ simulink
★★★ gui
★★★ arduino
★★★ scicos
★★ display
★ loops
★ kinect
★ dsp
★ gpu
★ nan
★ labview
★ image processing
cuda
axis
opnet
maple
opencv
source code
comsol
You have in mind a companion for matlab and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of matlab in all years. Click on graph for more.
matlab
mathematica
r