Amplitude of An Array

amplitude.js

var A = [-100, 2, 44, 0, 39, 5000010];
		
function amplitude(A){
			var n = A.length;
			var i;
			var min_val;
			var max_val;
			var allowed_min = 0;
			var allowed_max = 5000000;
			var max_elements = 3;
				
			console.log('n: '+n);
			if(n == 0 || n > max_elements)
				return -1;

			
			for(i = 0; i < n; i++){
				
				// detect if value is min value allowed
				if(A[i] <= allowed_min){
					A[i] = allowed_min;
				console.log('resetting val min');
					
				}
					
				// detect if value is max value allowed
				if(A[i] >= allowed_max){
					A[i] = allowed_max;
					console.log('al max set');
				
				}	
				
			
				if(i==0){
					console.log('setting defaults');
					min_val = A[i];
					max_val = A[i];
					
				}
				
				if(A[i] < min_val){
					console.log('min_val '+A[i]+ ' index: '+i);
					min_val = A[i];
	
				}
				
				if(A[i] > max_val){
					console.log('max_val '+A[i]+ ' index: '+i);
					max_val = A[i];
					
				}
				
				
			}

			return (max_val - min_val);
			
		}