In the paper,the discriminant function is derived from the Fisher principle to distinguish large pore paths in sandstone oil layers based on logging curves.

Methods: The dada from 22 patients with dermatomyositis complicated by malignant tumor and 43 patients with dermatomyositis without malignant tumor were analyzed and used to establish a discriminant function.

The geometry and information s distance discriminant function are used in our work,the first only calculates the model parameters,so it is simpl.

Through simplification of key normal equation set,the decision function is obtained and the effect of decision is not affected.

This approach is better than old ones where the decision function is calcul.

Normally we i-dentify the properties of unknown geological object by mul-tivariate discrimination function.

Discriminating function was proposed to comprehensively assess atmospheric quality and was applied in example analysis.

In this paper a quantitative data is derived to denote the degree of closeness of the correlation between the parameters of blood vessels and the gender of embryo,mean while,gender discriminating function is optimized and the direction of effort for further improvement is discussd also.

A new discriminating function is established more concisely by mathematical statistical method.