how can i generate a regular-expression of the form (...)(.*?)(...) in order to match the first element of both matrices?
i tried 
(Thermal expansion.*?steps\n +)(.*?)( +)
(Thermal expansion.*?steps\n {1,2})(.*?)( {1,2}

but neither did work. what am i missing?
(i need the (...)(.*?)(...) form because my program is scanning files which do not only contain numbers.


Thermal expansion (te) tensor [1/K] of composite
Convergence: 5.50149e-02 in 1000 steps
  3.2060307674e-04 -7.1247170199e-07 -5.3114135695e-06
 -7.1247170199e-07  8.4889588014e-06  1.0496506193e-06
 -5.3114135695e-06  1.0496506193e-06  2.9575863580e-04

Thermal expansion (te) tensor [1/K] of composite
Convergence: 5.50149e-02 in 1000 steps
 -3.2060307674e-04 -7.1247170199e-07 -5.3114135695e-06
  7.1247170199e-07  8.4889588014e-06 -1.0496506193e-06
 -5.3114135695e-06  1.0496506193e-06  2.9575863580e-04