## Fortran on Raspbian/Raspberry Pi – compiler options

I’ve just done a quick and nasty comparison of runtimes using GNU Fortran and the recommended compiler flags from here. I used a CFD code mentioned earlier.

Compiling as before (`gfortran euler.f`

) gave a runtime (using `time`

) of:

` CALCULATION CONVERGED IN 3490 ITERATIONS`

TO A CONVERGENCE LIMIT OF 4.99999987E-06

```
```

**real 1m6.156s
user 1m4.030s
sys 0m0.300s**

Next, I compiled using `gfortran `

with the following result:**-march=armv6 -mfpu=vfp -mfloat-abi=hard** euler.f

` CALCULATION CONVERGED IN 3490 ITERATIONS`

TO A CONVERGENCE LIMIT OF 4.99999987E-06

```
```

**real 1m5.127s
user 1m3.800s
sys 0m0.330s**

So a slight speed increase is shown. This difference would probably be amplified when more complex code is compiled. I had none to hand, alas.

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