I have a problem with a numerical integration. I have a 4x4x4x4 array that has for each entry an integral and I want to use `NIntegrate` to evaluate it. It gives me no problem, it's actually pretty fast. But if I increase the size of the array to 9x9x9x9 I get this message:

`NIntegrate::slwcon: Numerical integration converging too slowly; suspect one of the following: singularity, value of the integration is 0, highly oscillatory integrand, or WorkingPrecision too small.`

I increased the working precision already but it didn't help.