Volume integral term not using integrate() function

[Balavarun5]

Commit : 5a0b743

Issue

To calculate the volume integral term, integrate function should be used always. In case the integral is to be evaluated by Lobatto quadrature using N_LGL number of quadrature points, the algorithm can be made faster. However, this needs to be within a tested integrate() function. This is not the case.

Code duplication needs to be avoided to prevent bugs.

Also the when N_LGL != N_quad, the code is not vectorized. This too needs to be fixed.

[mchandra]

Also the when N_LGL != N_quad, the code is not vectorized. This too needs to be fixed.

Open a separate issue for this