pub fn lap(&self, i: usize, j: usize) -> f64 {
        self.get(i + 1, j) + self.get(i - 1, j) +
        self.get(i, j + 1) + self.get(i, j - 1) -
        self.get(i, j) * 4.0
    }
/// Returns the laplacian of the fluid quantity at grid cell (i, j)
Returns the laplacian of the fluid quantity at grid cell (i, j)
Returns the laplacian of the fluid quantity at grid cell ( i j )
pub fn lap(&self, i: usize, j: usize) -> f64 {
        self.get(i + 1, j) + self.get(i - 1, j) +
        self.get(i, j + 1) + self.get(i, j - 1) -
        self.get(i, j) * 4.0
    }
pub fn lap ( & self , i : usize , j : usize ) -> f64 { self . get ( i + 1 , j ) + self . get ( i - 1 , j ) + self . get ( i , j + 1 ) + self . get ( i , j - 1 ) - self . get ( i , j ) * 4.0 }
Returns the laplacian of the fluid quantity at grid cell (i, j)
Returns the laplacian of the fluid quantity at grid cell ( i j )
&self
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&self
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