These are collections of numbers, with one set of components for each node. They are referred to by names such as V101, V102, V201, ... , v300, v401, v402, ... . The last digit is used to distinguish components. You can get a picture of the current contents of the stack of vectors by clicking on the Vectors button on the Graphical User Interface. The vector stack can be controlled by commands like nostack, push and popp.
Vectors may be used in expressions and are the basis of many calculation procedures and graphical outputs. Global vectors will acquire values either by assembly or solution processes, or by being assigned the value of an expression. Local vectors (described in Section 3.3) exist only briefly during assembly and can also be assigned values within a problem environment. They may be initialised to be copies of global vectors.
Generally the order of statements in a problem does not matter, but the order can be important if assignments are made. Assignments must appear before the results are used. Boundary condition statements are implemented after element statements, so you cannot generally use the result of an assignment on a line beginning with b in a statement on a line beginning with e. Parameter values can also be set by assignment at global level.