The relationship between two nations is more on the basis of the role of the office and not merely the personality of the incumbent or even the ideology of the dispensation in power. This long term substratum in the relationship should never be given up for the sake of short term exigencies.
Iran has made horrible mistakes, it has also been subjected to horrible treatment. India can be and shall be a mitigating factor and never an aggravting influence as long as it abides by its well developed principle of non-alignment.