If statement

In Program QWIEN (written in QBASIC, Appendix A), x is initialized at 1 and incremented by 0.1 in line 3, which is given the statement number 10 for future reference. Be careful to differentiate between a statement number like 10 x = x -E. 1 and the product 10 times r which is 10%. A number a is calculated for x= 1.1 that is obviously too small so (a — 1) is less than 0 and the IF statement in line 5 sends conhol back to the statement numbered 10, which increments a by 0.1 again. This continues until (a — 1) > 0, whereupon control exits from the loop and prints the result for a and a . 

An IF statement could be used to set the value of the heating rate equal to zero, once a fractional conversion of 90 per cent is achieved. 

The IF-statements in the listings prevent the solute concentrations from going below 0.0001 (a value near to zero). This is because these concentrations exist in the denominators of some of the expressions used in the program and therefore cannot be allowed to become zero. 

As an alternative numerical experiment, I suppress all ice formation by modifying subroutine SWALBEDO. The modifications are to set the fraction of the ocean covered by sea ice to zero, regardless of temperature, and to set an unattainably low temperature limit in the IF statement that branches to temperature-dependent albedo on land. The program is listed as DAV11. 

I imagine that respiration adds total dissolved carbon at an isotope ratio of delcorg, specified by subroutine SPECS. I further assume that dissolution adds total carbon at an isotope ratio delcarb, also specified in subroutine SPECS. The precipitation of calcium carbonate removes total carbon at an isotope ratio equal to the isotope ratio of the pore water. There is no fractionation associated with either dissolution or precipitation in this system. Because the isotopic value associated with precipitation is different from that associated with dissolution, I have to test the sign of diss before adding the dissolution term to the equation for the rate of change of the isotope ratio in subroutine EQUATIONS. This test is made in the IF statements in this subroutine. 

If statements ensure preconditions for their branches. The postcondition of the whole thing is an OR of the branches ... 

The step feeding is programmed using nested if statements. 19 time points with a time interval of PUMPTIME (timel to time time 19) are defined at which flow rate is switched to the next predefined value F2 to F20. 

In general the IF-THEN-ELSE conditional statement form is used, combined with the inequality and/or possibilities as found in the HELP. This can involve a switching from one equation to another within this statement. Another way is to use flags or constants that take values of 0 or 1 and are multiplied by terms in the equations to achieve the desired results. The programs RUN and RELUY contain such programming. As shown in RUN, nesting of multiple IF statements is possible ... 

To give an example, the following form of argument is known as modus ponens "If statement A implies conclusion B, and we know A to be true, then we may conclude B" and may be represented as follows ... 

Beyond submitting any known prior art, parties of interest must confirm that the patent application is an accurate reflection of their invention. If statements or data characterizing the invention in the specification are relied on to support the patentability of one or more of the claims in the patent application then those statements or that data need to be accurate and also should be representative of the claimed invention. This also applies to data and statements in declarations and related documents submitted to the patent office to support the patentability of the claimed invention selective disclosure of only favorable data while omitting contradicting data is frequently not a good idea ( when in doubt, send it out ).77... 

Textual descriptions of the exposure assessment results might be useful if statements about the mean, the central tendency estimate (median) or a selected quantile of the exposure distribution are given without a description of uncertainty. However, each of the point estimates mentioned will have a different level of uncertainty with respect to model assumptions, database and calculation method. A typical wording to describe results might be, for example ... 

There is only a small difference between the two forms and in the program, there is need for only a small IF-statement split, to handle both in the same code stretch. In fact, in UMDE DIRECT the BI form is first assumed, and then, if BDF is found to hold, the change is made from one to the other. 

These IF statements are really a form of discrete decision making embedded within the model. One possible approach to remove the difficulties it caused is to move the discrete decisions to the outside of the model and the continuous variable optimizer. For example, the friction factor equation can be selected to be the laminar one irrespective of the Reynolds number that is computed later. Constraints can be added to forbid movement outside the laminar region or to forbid movement too far outside the laminar region. If the solution to the well-behaved continuous variable optimization problem (it is solved with few iterations) is on such a constraint boundary, tests can be made to see if crossing the constraint boundary can improve the objective function. If so, the boundary is crossed—i.e., a new value is given to the discrete decision, etc. 

The default stepsize is +1, and under these circumstances it is possible to omit the step statement. Loops are concluded by a Next statement. If statements must be on one line ending with Then, and a typical syntax is as follows ... 

On the answer sheet, you will mark true (T) or false (F) for each statement, and you will mark "correct explanation (CE) ONLY if statement II is a correct explanation of statement I. Here are sample directions for this kind of question, followed by two examples and a sample of a correctly marked answer sheet. 

Directions Each question below consists of two statements. For each question, determine whether statement I in the leftmost column is true or false and whether statement II in the rightmost column is true or false. Fill in the corresponding T or F ovals on the answer sheet provided. Fill in the oval labeled CE only if statement II correctly explains statement I. 

An if statement represents logic that is conditionally controlled. Here is an example. 

The semantics of the always statement specifies that every time an event occurs on Phy or Ones (variables present in the event list), the if statement executes and the variable Z gets the value of Ones incremented by 1 if Phy is a 1. If Phy is a 0, the value in Z is retained this is done using latches. 

A general rule for latch inferencing is that if a variable is not assigned in all possible executions of an always statement (for example, when a variable is not assigned in all branches of an if statement), then a latch is inferred. 

A case statement behaves like a nested if statement, that is, the value of the case expression (Op) is checked with the first case item (ADD), if it does not match, the second case item (SUB) is checked and so on. The equivalent i f statement for the above case statement is shown next. 

The semantics of this casex statement can best be expressed by its equivalent if statement. 

A latch may be inferred for a variable assigned in a case statement, just like in an if statement. If a variable is not assigned a value in all possible executions of the always statement, such as when a variable is assigned a value in only some branches of a case statement, a latch is inferred for that variable. See the following example. 

The equivalent behavior of the case statement is expressed in the following if statement. 

A variable declared locally within an always statement is also inferred as a latch if it is incompletely assigned in a conditional statement (if statement or case statement). This is shown in the following module. 

So far we have talked about synthesizing simple D-type flip-flops. What if we wanted to infer a flip-flop with asynchronous preset and clear To generate such a flip-flop, a special form of if statement has to be used. This is best shown with an example template. 

If negedge B is present in event list, then the if statement starts of as if (IB)... 

The value z is used to generate a three-state gate. The value z can be assigned to a variable in an assignment statement however for synthesis, such an assignment must occur under the control of a condition, either in an if statement, or in a case statement. Here is an example. 

Resource allocation refers to the process of sharing an arithmetic-logic-unit (ALU) under mutually-exclusive conditions. Consider the following if statement. 

II Assume that the second assignment is executed every // time the first statement is executed. Note that this // assumption may not be true if either of the statements //is inside an if statement or a case statement. 

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