f77coder: Please correct me if I'm wrong, but it seems that you have replaced the code of your original post with code derived, more or less, from a subsequent post by Laurent_R, and without citing any change to the OP. I had first composed a more snarky reply, but will confine myself to this: choroba and Laurent_R now look foolish for having posted (apparently) completely irrelevant replies to (what now appears as) your OP. If I read this thread aright, what you have done is akin to pulling the chair out from under someone as they are sitting down to dine! Please feel free to make whatever additions/updates/corrections/etc you feel are needed, but for the sake of courtesy and clarity, please leave the original material and cite your changes!

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